Add functionality to change the name of the main branch

[ViktorLindgren95]

Hello, the provider was missing an api endpoint ive been using and to not have to use data resources via the http provider which causes a lot of redundant calls, i added it to the provider.

• Added resource_sonarqube_project_main_branch.go
• this adds the ability to set,change and delete the default branch name
• Added resource_sonarqube_project_main_branch_test.go
• Ive both ran the test via the makefile with the docker file and also done a local test where i span up my own sonarqube instance and ran terraform against it with the compiled provider. both sucessfull
• Added Documentation to explain how to use it

A couple of things, this is my first ever terraform provider code so there is probably a lot of things not perfect. im sorry in advance. There is currently two TODOs that i dont know if is should make or not:

• Imports. Firstly when to support import, and is it needed here. the setting of the main branch is kinda fire and forget, it dosent even return an object its a 204 call
• When deleting the branch object, we currently just revert the main branch to main, which is the default for sonarqube. the alternative im considering is perhaps reading the sonarqube instance setting for default branch and setting it to that. i dont know if thats good practice to rely on another api call to do a delete function

[ViktorLindgren95]

@jdamata I cannot add a reviewer, dont know if this is nice to do but ... hi

[jdamata]

Was this meant to be closed?

[jdamata]

Was this meant to be closed?

Nvm. I see you added this to the other pr.