Move headers Part 2

[kodebach]

What happens in this PR?

Continuing from #4920, this PR includes further progress on the decisions mentioned in #4920. The goal for this PR is to finish all the header changes, i.e. src/include should (basically) have it's new contents completed with this PR.

• 38b7e17d3fa69fdfc40dbb75bb7036b8e52809dc splits the old_helper.h header into more modular units
• 5fe5bc11b03848b20bdc9877507e102a606f4164 is the only automated commit in this PR, it updates the files that used old_helper.h
• 807a51f44a8c58173ae234588c6ad7d9a9cf6720 and 2e97bea5a2fb44b16798c27c8ceedc49f1f17177 are the formatting fixes and manual updates necessary after the automated commit
• b455e371c0dc0a2b53f2955cd7006d229ff17831 until b03b163359dbc34800153489b8df08dac44d28c3 were done manually. They split kdbprivate.h into more modular units. I did this manually, because I wanted to verify where kdbprivate.h is used and why. Partly to ensure there isn't some place that shouldn't use it and partly to inform how kdbprivate.h should be split up.
• All following commits are additional fixes required to make things actually work

Hints for reviewers

As with #4920 this PR has a large number of changed files. Most of them once again are only updated #includes.

• src/include/** split up, moved, rearranged headers according to decisions (the thing that causes all the other changes)
• src/libs/elektra/CMakeLists.txt CMake update, not sure if it's needed here, may have slipped into the wrong commit and may only required by #4941, but doesn't break anything
• src/libs/elektra/backends.h new header extracted from kdbprivate.h
• src/libs/elektra/hooks.h new header extracted from kdbprivate.h
• src/libs/elektra/internal.c moved elektraMemcpy and elektraMemmove to keyset.c
• src/libs/elektra/keyset.c adds a new DEFAULT_KEYSET_SIZE because the old KEYSET_SIZE is no longer in a header AND moved elektraMemcpy and elektraMemmove from internal.c
• src/libs/elektra/keytest.c removal of keyIs* functions which are now static inline aliases
• src/libs/elektra/symbols.map now exports elektraReadNamespace as private (no idea how it worked before)
• src/libs/highlevel/elektra.h new header extracted from kdbprivate.h
• src/plugins/xmltool/xmltool.h removal of unnecessary redeclaration of elektraStrLen
• src/tools/kdb/gen/templates/collect.sh adds a mkdir -p (no idea what it is needed now)
• tests/ctest/test_keyset_cow.c adds a new DEFAULT_KEYSET_SIZE because the old KEYSET_SIZE is no longer in a header

All other changed files are only changes in #includes.

Those are the main changes of this PR, below are some extra fixes to please the CI:

• doc/man/** not sure why those changes were needed, but the CI complained
• scripts/docker/openwrt/sdk/Dockerfile update OpenWrt image (should happen on master at some point too)
• tests/linkchecker.whitelist add https://opensesame.libelektra.org and https://pull.libelektra.org because of certificate issues

Basics

• [ ] Short descriptions of your changes are in the release notes (added as entry in doc/news/_preparation_next_release.md which contains _(my name)_) Please always add them to the release notes.
• [ ] Details of what you changed are in commit messages (first line should have module: short statement syntax)
• [ ] References to issues, e.g. close #X, are in the commit messages.
• [ ] The buildservers are happy. If not, fix in this order:
  • add a line in doc/news/_preparation_next_release.md
  • reformat the code with scripts/dev/reformat-all
  • make all unit tests pass
  • fix all memleaks
  • fix the CI itself (or rebase if already fixed)
• [ ] The PR is rebased with current master.

Checklist

• [ ] I added unit tests for my code
• [ ] I fully described what my PR does in the documentation (not in the PR description)
• [ ] I fixed all affected documentation (see Documentation Guidelines)
• [ ] I fixed all affected decisions (see Decision Process)
• [ ] I added code comments, logging, and assertions as appropriate (see Coding Guidelines)
• [ ] I updated all meta data (e.g. README.md of plugins and METADATA.ini)
• [ ] I mentioned every code not directly written by me in reuse syntax

Review

• [ ] Documentation is introductory, concise, good to read and describes everything what the PR does
• [ ] Examples are well chosen and understandable
• [ ] Code is conforming to our Coding Guidelines
• [ ] APIs are conforming to our Design Guidelines
• [ ] Code is consistent to our Design Decisions

Labels

• [ ] Add the "work in progress" label if you do not want the PR to be reviewed yet.
• [ ] Add the "ready to merge" label if everything is done and no further pushes are planned by you.

[kodebach]

elektraMalloc et al. are likely broken (for some use cases) in this PR. See https://github.com/kodebach/libelektra/commit/dd1b9ec85c16d0e68b35e5f55592f18f386ab0c8 for how I plan to rectify that. This works (*) and I'm pretty sure is an improvement. It definitely allows the compiler to perform more analysis, since I needed https://github.com/kodebach/libelektra/commit/bd1ff1ed9001a7b997a90d089562b99cc67ef677 to fix some GCC warnings after the change. It may also improve performance, since the compiler might optimize differently. However, I'm also open to reverting these changes and going back to having elektraMalloc et al. as normal functions in libelektra-base like elektraFormat.

(*) the Checks in https://github.com/kodebach/libelektra/pull/41 (previous incarnation of these PRs) compile

EDIT: I decided to instead leave the functions unchanged for this PR, and only introduce them as static inline in #4941.

[kodebach]

@lawli3t @atmaxinger @hannes99 @flo91 @lukashartl If you review, please read the PR description it explains what's happening in this PR and which files have interesting changes.

[kodebach]

jenkins build libelektra please

[kodebach]

jenkins build libelektra please