[MPESW-2467] FESA xml completion

Context

• https://its.cern.ch/jira/browse/MPESW-2467

What was done

• Fetch xml schemas for the relevant FESA version
• Mount them in the container

TODO

• Discourse documentation on how to setup autocompletion

QA

• Ran the setup script again and test autocompletion with a VS Code extension

Review objectives

• assessment of code functionality
• assessment of code quality
• identifying potential refactorings / logic common to other projects
• knowledge sharing