add git pre-commit hook to prevent mistakes

See merge request pub/open-source-case-studies!27

Consider running 'git config core.hooksPath .githooks' in your OSCS clone
to enable it.

Sync with frama-c master after MR !3660 and !3698

See merge request pub/open-source-case-studies!25

Also avoids a failure on a recursive function without specification
(function factorial in file 00168.c).

Adds annotations to disable partitioning in file 00040.c to avoid combinatorial
explosion.

add description + URL per directory; add summary table in Markdown

See merge request pub/open-source-case-studies!23

[x509-parser] add E-ACSL target; add test DER certificate

See merge request pub/open-source-case-studies!22

Note: several "ok" tests still contain warnings; in some cases, they seem
inevitable, but others can be improved by adding C stubs, ACSL annotations,
or improving the precision in other ways. They may also contain real bugs
which have not yet been patched.