Modernise build structure
Re-opening of !5 (merged) (wasn't actually merged despite what GitLab may tell you!)
- Cross-compilable
- Softloadable builds install files in ResourceFS (it looks like this was once the case but the feature was dropped at some point). To facillitate this, switch component to use the CModule shared makefile
- Consolidate and complete
.gitignore - Enable GitLab CI and address issues identified