Add initial version

[tkilias]

Background

• Extract exaslct into dedicated repository script-languages-release#243

Tasks:

• extract the exaslct_src from https://github.com/exasol/script-languages
• create a proper poetry package out of exaslct_src
• package exaslct as docker image and provide a starter script which can run it in other repositories solely from docker image
• Setup CI