TA-3751: Migrate Pacman commands

[Zgjim Haziri (ZgjimHaziri)]

Description

• Migrated Pacman commands into the new structure, based on this doc.
• The code logic is copy-pasted, besides some things like e.g. restructuring, command definition format.
• Migrated existing tests as they are, with only some minor changes in the test config setup to fit the new test config of the tool.
• Some renaming, especially in used Studio service/api variables.
• Created separate services for variableService, which was previously in Studio and contained all variable functionality regardless if Studio or Pacman.
• Changed some static mocking that was done to verify calls to Studio APIs, to verify directly the API call with httpClient.

Relevant links

Jira issue: https://celonis.atlassian.net/browse/TA-3751

Notes

I would suggest to review the code along with some functional testing of the commands. This will make easier reviewing the large number of added lines here.

Checklist

• I have self-reviewed this PR
• I have tested the change and proved that it works in different scenarios
• I have updated docs if needed