Also: merged Makefile.serverdoc into Makefile.documentation

- used to indicate whether tests require the FRAMAC_WP_CACHEDIR variable

- more intuitive name for tests directories
- single way to build PTEST_ALIASES

- making the dev guide (and especially its checks over the tutorial code)
should be done against up-to-date frama-c binaries.

- `Boot` module is referenced in the index of devman, it ought to be
present in the API documentation

This reverts merge request !3615

François Bobot authored 3 years ago and Allan Blanchard committed 2 years ago

  Updated more frequently, uses dune so better META file

Allow estimate-difficulty to be exported (in Linux/macOS/Windows) as
independent executable, so that it can be used without having to install
Frama-C.