MAINT-1974 Added configurable branch to refset types

[hurtigcodes]

Added a config option for setting up reference set types on other branches than MAIN, which was hardcoded before.

Thought of loading all available branches during app init and config all refset types to all there and then, but this should be good enough for our needs.

"refsets.branch" defaults to MAIN if it's unset in application.properties. If configured branch don't exist exception is thrown (java.lang.IllegalArgumentException: Branch 'BLABLA' does not exist.) and app fails to start.

[hurtigcodes]

OK now it should be ready for develop

[kaicode]

Jira ticket MAINT-1974 has been created and handed over to the technical team.

[hurtigcodes]

Hi, any updates on this PR? :)

[CoderMChu]

@hurtigcodes Yes it looks good. I will merge it now. Thanks.