cleaning up controller.xql:
- rework login domain: was server-wide, now specific to cr-xq instance
- some syntax + formatting cleanup
- adding documentation
repo-utils:xsl-doc() and repo-utils:serialise-as():
- some minor code cleanup
- added documentation
updating .gitignore
- reworking config.xqm to use METS-catalog, especially
  config:param-value()
- adding in-code documentation to config.xqm
adding some initial documentation about the new METS based cr-project data model