Tag and make a new release.

[9600]

Update master and make repo release-ready:

• Match gr-3.8 and gr-3.9 branches' .clang-format files and reformat the contents to match. This will make porting future changes practical.
• Add C++ codegen to GRC
• Bump master branch GNU Radio version #90
• Clean up code
  • std::cout -> GNU Radio logging
  • No exit() calls from a shared library
  • Address valid warnings (e.g. missing returns from non-void functions)

Tag and make a new release with:

• Windows assets
• Ubuntu PPA packages (bionic, focal and jammy)

[ncorgan]

@9600 While cleaning up the 3.9 MR and getting feature parity with 3.8, I added some release preparations task to the issue. Most of these are minor things, maybe a couple added hours of work. Any major red flags here?

[9600]

@ncorgan Thanks! Can't see any, LGTM.