Plugin.xml extension registration

Reports problems with extension registration in plugin.xml.

The following problems are reported:

• Missing language declaration. If the extension does not target a specific language, use quick fix to create an explicit declaration for "any language".

• Inspections: missing attributes

• Services: redundant serviceInterface declaration

• com.intellij.stubElementTypeHolder without externalIdPrefix, see Stub Indexes

New in 2022.3