Context:
The migration step in our build pipeline or rather the `upgrade-es-schema` tests are using an ant script to execute the behavior described in INFRA-899. However, it makes it hard to read since we're wrapping JSON wrapped in Bash for curl is wrapped in Ant XML. To make that more readable we should have a single script that contains all the steps and is called from the pom file.
This also improves the separation of concerns since maven should not be responsible to execute test setups.

AT:

• the migration step behavior is moved to a single script
• the upgrade data script step behavior is moved to a single script
• the duplicated code parts in the two scripts are merged into reused functions
• the two identical docker-compose files are merged into one that's used in both upgrade scripts
• change the default path for storing the ES snapshot from /usr/share/elasticsearch/essnapshots to /tmp to avoid permission issues
• cleanup Christians remarks from this PR: https://github.com/camunda/camunda-optimize/pull/1446

Hint:

• Think about if it makes sense to use a javascript file instead of a bash script
• given we already use groovy in build pipelines and already have java available groovy scripts might also be a viable alternative https://groovy.github.io/gmaven/groovy-maven-plugin/execute.html