Separate security scanned lockfile

[miikkako]

Similar changes to iqm-finland/iqm-client#159, no functional changes to code. In this PR:

• Supply a lockfile with package checksums which is scanned for vulnerabilities by aikido.
• test_requirements_lock ci job verifies the lockfile is always up to date. Only the direct top-level deps specified in pyproject.toml are upgraded by the script.
• tox is removed from dependencies and its envs from tox.ini are converted into simple executable files containing commands (test, format, docbuild)

Piggyback:

• docs are build with -W (treat warnings as errors). A couple of warnings fixes in this PR
• gen_licenses_info ci job to generate a list of dependency licenses for new tagged releases