Shared infrastructure between GCV and GCV idea plugin aren't shared

## What happened?

Currently both GCV and the idea plugin have to parse the `gcv-maven-repositories.xml` file but they have seperate implementations of the classes todo this. This means if one changes the other breaks

## What did you want to happen?

The code for parsing the XML should be stored in a separate project in this repo which both reference so there is a single source of truth
