Extract dependency check bash scripts for python, pip and docker into own repository

[tkilias]

Background

• The branch https://github.com/exasol/script-languages-release/tree/feature/run_exaslct_in_docker contains scripts for checking the availability of certain dependencies, such as python, pip and docker
• These scripts are useful for the script-language-container-tool, the integration-test-docker-environment and maybe also other projects
• However, the branch itself is obsolete, and only the check scripts are still useful, so we should extract them into their repository

[tkilias]

Mainly done with https://github.com/exasol/integration-test-docker-environment/pull/180, this ticket is not needed anymore. If necessary, this is the commit where you can find the scripts. https://github.com/exasol/script-languages-release/commit/47505cbd6ca0b9fb7cafecba118e17ace461618b