New rule S6960 for C#: Controllers should not have too many responsibilities

[antonioaversa]

Fixes #9089

[antonioaversa]

Moved back to draft as the Disjoint Sets primitives have been extracted into a dedicated class and a dedicated PR:
#9145

This PR now has #9145 as a dependency.

[gregory-paidis-sonarsource]

Amazing work, very clever and clean implementation 💘
Left some questions and some cleaning-up suggestions.
I did not go over the test cases again, I trust that you copied what was already reviewed on the RSPEC side.
If there are changes, please let me know with a comment where I should look.

[antonioaversa]

@gregory-paidis-sonarsource I have undrafted the PR, after changing the base to the PR with the Disjoint Sets data structure.
You can now go for a second round of review.

[gregory-paidis-sonarsource]

LGTM, only one open comment remaining from me which is optional

[mary-georgiou-sonarsource]

Looks good, left only two small suggestions.

I have a couple of questions, as I missed the previous meeting:

1. How come we did not go with the attributes, and instead take into account all classes/interfaces by default?
2. Do you plan to exclude abstract controllers before we merge, or will you do a small update PR just for that?

1. We decided to not rush adding the attributes as they cannot be removed once added. It would be problematic for the users.
2. I've added the abstract classes exception.

[mary-georgiou-sonarsource]

@gregory-paidis-sonarsource BTW, I'd ignore the code smell as it won't fix for us.

[sonarqubecloud]

Quality Gate passed for 'Sonar .NET Java Plugin'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[sonarqubecloud]

Quality Gate passed for 'SonarAnalyzer for .NET'

Issues
0 New issues
2 Accepted issues

Measures
0 Security Hotspots
95.3% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[gregory-paidis-sonarsource]

LGTM