Update Doxygen file blocks to remove copyright and license information

[Patater]

This PR separates the copyright and license information from the Doxygen documentation blocks. The documentation was also updated to have file and brief blocks for all header files in include/mbedtls/.

Work done by @dgreen-arm

Testing done:

• make apidoc
• Open apidoc/index.html and browse around a bit
  • Verified that copyright and license info does not appear in the "More..."-linked Detailed Description section of files
  • Verified that copyright and license info did appear in the "More..."-linked Detailed Description section of files on the live website (https://tls.mbed.org/api/base64_8h.html#details)
• Successfully ran ./tests/scripts/doxygen.sh
• Successfully ran ./tests/scripts/check-doxy-blocks.sh
• Successfully ran all.sh

[k-stachowiak]

I checked all the headers in the /include directory and I can confirm the Doxygen blocks are separated from the copyright notices.

I have noticed that this is not true for the doxygen/input files, but I'm not sure if that is even an issue and it reaches beyond the scope of this PR. So I'm just leaving this comment.

[gilles-peskine-arm]

FYI it's important to check scripts/config.pl full && make apidoc. I'm doing this now.

On the other hand, scripts/config.pl full && make apidoc, which is what scripts/apidoc_full.sh does, is known to be incomplete. I'm not sure what that script is really for.

[gilles-peskine-arm]

@k-stachowiak @Patater Indeed the files in doxygen/input need to be updated. To check:

grep Copyright apidoc/*.html | grep -v _source.html

It would be best to update the sample configurations in config as well for consistency. They aren't normally typeset, but someone could take one and decide to typeset the documentation.

[gilles-peskine-arm]

Everything that has been done, looks good (removed copyright from Doxygen output, kept it in the source files, and no other changed).

I sampled the rendered HTML of scripts/config.pl full && make apidoc, and I also sampled the diff between the corresponding output before and after the patch.

However, as noted, this is incomplete. Please update the files in configs/ and in doxygen/input/ as well.

[Patater]

The files in configs/ and in doxygen/input/ have now been updated.

All previously mentioned testing performed by me has been redone, with the exception of running all.sh which hasn't finished yet.

[gilles-peskine-arm]

It all looks good now.

[Patater]

all.sh has finished running, and it passed.

[Patater]

CI failure is FreeBSD timing test

15:53:03 
15:53:03   TIMING tests note: will take some time!
15:53:03   TIMING test #1 (set_alarm / get_timer): passed
15:53:03   TIMING test #2 (set/get_delay        ): failed at line 459
15:53:03  cycles=0 ratio=0 millisecs=1001 secs=1 hardfail=0 a=800 b=400
15:53:03  elapsed(hires)=2308 elapsed(ctx)=1307 status(ctx)=2
15:53:03   Executed 23 test suites
15:53:03 
15:53:03   [ 1 tests FAIL ]