Adding installation instructions for Linux

[llrs]

This PR is part of the GSOD-2022 adding a brief instructions how to install R for linux (Ubuntu) from source.

I expanded a bit the introduction of the different types of R versions available and the versioning system used. Maybe a simple graph explaining the relationships between different R versions would help, something like:

flowchart LR;
    r_devel[r-devel]
    bug_fix([Bug fix])
    r_patched[r-patched]
    r_release[r-release]
    bug_fix-->r_devel;
    bug_fix-->r_patched;
    new_feature([New feature])-->r_devel;
    r_patched-->r_release;
    r_devel --breaking change--> r_release;

Following the python quick reference I organized the instructions as a list. But I left the windows and macOS bits out (I haven't checked yet if these instructions would work there).
In the python book they also have on the list how to create patches and submit them. I mention it at the end of the installation instructions.

I assumed users have all the third party requirements of R. From the discussions in the slack, it seems that how to install those third-party dependencies (or at least a list of them) might help R sysadmins. I'm not sure how to collect those besides looking to dependencies in r-base for Ubuntu or the list of the SUSE Linux instruction @HenrikBengtsson mentioned.

The rest of the chapter is left as it was (but with minor changes: whitespaces and having each sentence in a new line).

[nbenn]

@hturner Do we want to let this grow a bit (wait until there's something on macOS as well) before broadening reviewer scope? Or should I add a couple review requests?

[llrs]

Many thanks for the review @nbenn, I will check the remaining comments and update the PR. I think it is better to merge soon and if there is something more to tweak we can check the whole chapter at the end.

I don't think using installing binaries is enough to contribute from Windows (although it can be useful to check if a given patch fixed an issue), for that I'm trying to build from source(Currently stuck with finding the right compiler within RTools42 & MSYG). In addition, there is some recommendations no longer up to date (#29).

[llrs]

I think all the comments have been addressed: If you, @nbenn and @hturner, could review the last changes let me know if it is ready to merge.

[SaranjeetKaur]

@all-contributors please add @llrs for content, question, research, doc, example

[allcontributors[bot]]

@SaranjeetKaur

I've put up a pull request to add @llrs! :tada:

[llrs]

I'll merge this PR as the issue with the Ubuntu system packages is "solved". It could be that with miktex installed all the 8 texlive-* would be replaced by a single miktex dependency too. I sent a message for fedora dependencies, but that and any other improvement can be later improved via new PR .