Follow-up of #1364.

• Do we need to run any checks on pushes to master if we also run them on pull requests and we make pull requests for everything?
• Run certain workflows only if the main workflow succeeds (e.g. emscripten, mingw, ...)
• Make sure Fuzz lou_translateString is not run in forks
• Run code formatting check only on changes to C files in the "liblouis" or "tools" directories
• Run sanitizer checks only on changes to C files in the "liblouis" or "tools" directories
• Run mingw workflow only on changes to C files in the "liblouis" or "tools" directories
• Run license check only on changes in the "tables" directory (done for pushes to master but not for pull requests)
• Extend the code formatting check with a check to see if fuzzing.yml needs to be updated
• Some actions could be combined in a single workflow, e.g metadata, license and code formatting and checks, and the check to see if fuzzing.yml needs to be updated
• Run make distcheck only if make check succeeds
• The emscripten workflow could in principle only be executed on changes to C code. The reason why we do it on all changes is because we also want to apply table changes to https://github.com/liblouis/js-build/tree/master/tables. We could try to find an alternative for that. Note that we don't need table and test changes for the purpose of re-running tests because the tests are currently disabled. Also note that uploading build-no-tables-utf32.js to the "snapshot" release should ideally only be done when a win32 artifact is also uploaded, otherwise the reference to the commit hash in the release description isn't technically correct. Currently the mingw workflow is run only on changes to C code, but note that it would also make sense to do it on table (and test) changes, because the workflow runs the tests, and the resulting build artifact includes the tables.