Added a global preference for user settings.xml for Maven projects

[Achal1607]

Added a new preference in the MavenSettings for custom user settings.xml file.
Also, exposed it to the LSP
Below is the screenshot for the new preference Netbeans IDE UI:

Closes #4263

[lahodaj]

On a cursory look, seems reasonable to me. @sdedic - any comments? Thanks!

[mbien]

useful feature! I found two issues while testing:

• the settings.xml node in the Project Files folder of maven projects is always linking to the default location (even after restart)
• the profile switcher combo box in the main tool bar is only updating after restart (edit: i tested this by having different profiles in the custom-settings.xml)

[mbien]

nitpick:

        JsonPrimitive newMavenUserSettingsPath = c instanceof JsonPrimitive jp ? jp : null;

[Achal1607]

useful feature! I found two issues while testing:

• the settings.xml node in the Project Files folder of maven projects is always linking to the default location (even after restart)
• the profile switcher combo box in the main tool bar is only updating after restart (edit: i tested this by having different profiles in the custom-settings.xml)

I have fixed both the issues @mbien. Can you please review again? Thanks for pointing it out.

[Achal1607]

The tests are passing locally, can someone please re-run the tests?

[neilcsmith-net]

Thanks for this addition, although I'm not sure it fully addresses #4263 Ideally, NetBeans should always match the settings Maven would use. So, settings in global execution options, project configuration, (in v4) project settings, etc. would ideally all work. This seems good as a stopgap solution, but will probably all need a rethink when we come to upgrading to Maven 4.