Remove obsolete scripts

[mpg]

Remove the following scripts from the development branch:

• all-in-docker.sh, ssl-opt-in-docker.sh, basic-in-docker.sh, docker_env.sh, tests/docker/bionic/Dockerfile - obsoleted by our CI images now being publicly available, see https://github.com/Mbed-TLS/mbedtls-test?tab=readme-ov-file#quick-start and https://github.com/Mbed-TLS/mbedtls-test/blob/main/resources/docker_files/README.md
• travis-log-failure.sh - we're no longer running tests on Travis and this isn't used anywhere else (as the name suggests and git grep in the main repo and mbedtls-test confirmed).
• scripts/windows_msbuild.bat - we used to run this on Travis, but it's no longer used anywhere
• config.pl - meant to ease the transition to config.py, should have been removed in 3.0 already.
• tcp_client.pl - was used by ssl-opt.sh, but no longer, and we can now do the same more easily in test_suite_ssl, so let's remove, as well as the line TCP_CLIENT="$PERL scripts/tcp_client.pl" in ssl-opt.sh.

Until now there was no strong reason to remove those scripts, but now if we kept them we'd have to move them to the framework, so that's a good reason to finally remove them instead.

Note: out of an abundance of caution, let's remove them only from the development branch.