Deprecations: preparation for VUnit-V

[umarcor]

There are several packages and features in VUnit that have been deprecated for months. Maybe it's time to decide about removing all of them at once. We are about to release v4.6.0. If we include breaking changes, the next one would be v5.0.0. I thought it might be fun to use roman numbers and have a banner imitating RISC-V:

Anyway, that's the least important. We need to review which features were marked/announced as deprecated already, and which need to be marked in v4.6.0 so we can then remove them in v5. There are milestone v5.0.0 and label 'breaking change' for keeping track of issues related to this deprecation window.

• [x] #559
  • The deprecation of compile_builtins and vunit.verilog, along with replacing add_builtins with add_verilog_builtins and add_vhdl_builtins was announced already (see #757). #764 is to be merged in a future v5 release.
• [x] #600
  • Deprecation was announced 2y ago.
• [x] #932
  • Deprecation was announced 2y ago.
• [x] #742
  • This is to get rid of the custom code in Compliance-Tests (https://github.com/VHDL/Compliance-Tests/blob/master/run.py#L30-L64). That was written before option --keep-compiling was added to VUnit. However, we need it to keep running, not to stop after compilation. Anyway, it is strictly a breaking change, as proven by the failing CI test.
• [x] #933
• [ ] #760
• [ ] #520
  • #511