[BUILD][MISC] Rewritten all Makefiles for efficiency and correctness

[benliao1]

In the past, our builds / Makefiles had two problems:

1. They were inefficient (i.e. compiling all the tests took a really long time; or compiling all of Runtime)
2. (more importantly) they were "incorrect", in the sense that you could change the dependency of a file, run ./runtime build again, and not have all dependent files be rebuilt again.

This PR fixes these issues by:

1. Compiling all source files into object files first, then linking them together into executables
2. Using the -MMD and -MP compiler flags to autogenerate dependency files for each object file

This does make our Makefiles somewhat more complex, however, I tried my best to keep the number of syntax features to a minimum while still getting the job done in a more or less general way.

In addition to the Makefile changes, I fixed / cleaned up / added a few things:

• Reintroduced the PR code format checking job that was in the old Travis CI job but was left out of the original Github Workflows PR
• Changed all #include of Runtime headers to use angle brackets instead of quotes with relative path names (better readability!) since our Makefiles are able to support that now
• Fixed a few compiler type mismatch warnings in dev_handler.c and dev_handler_message.c, as well as incorrect use of printf in test.c
• Cleaned up .gitignore so as to only ignore the necessary folders / files; we used to have a copypasta .gitignore from somewhere that had way too many entries and might lead to confusion for new members
• Removed a couple of the clang files in the root directory to reduce confusion for new members; I also removed the run_clang_format.py script and replaced it with a much simpler, in-house script that I wrote in bash that does basically the same thing. Run a check with ./runtime format check and fix code to comply with the standard with ./runtime format fix

[benliao1]

A lot of small extra cleanup / QOL items were added in this PR. The tests/Makefile in particular got a lot of extra functionality, i.e. it is now possible to run all of the following:

• make net_handler_cli to make just the net_handler_cli
• make cli to make all the CLIs, but nothing else
• make GeneralTestDevice to make just the GeneralTestDevice
• make devices to make all virtual devices, but nothing else
• make tc_150_1 to make just tc_150_1
• make integration/tc_150_1 (same as above)
• make tests to make all test programs
• make all to make all devices, CLIs, and tests
• make help to list all of the above options

I also managed to silence some formatting warnings in the compilation that was cluttering our CI output, and write our own formatting bash script specific to Runtime that is much much simpler than the Python script we had before.

The test script now can take ./runtime test tc_150_1. You used to have to specify either the integration/ or performance/ folders, i.e. with ./runtime test integration/tc_150_1. Both of these now work.

I also deleted the scripts/install_raspi.sh and scripts/provision_raspi.sh scripts because they aren't being referred to and don't really belong in the repo. We should create more wiki pages with how to provision / install Runtime on Raspberry Pi's (or put it in the root README.md)!