rascal-eclipse: EclipseIDEServices should add meaningful implementations for new methods in IDEServices

[jurgenvinju]

Describe the bug

The following methods were added to IDEServices facilitate rascal-language-servers and are now scattered over other classes in rascal-eclipse:

• [x] browse(URI uri)
• [ ] edit(ISourceLocation path)
• [ ] resolveProjectLocation(ISourceLocation input)
• [ ] registerLanguage(IConstructor language) (requires access to util::LanguageServer from rascal-language-servers)
• [ ] applyDocumentsEdits(IList edits)
• [ ] showMessage(IConstructor message)
• [ ] logMessage(IConstructor msg)
• [ ] registerDiagnostics(IList messages)
• [ ] unregisterDiagnostics(IList resources)
• [ ] registerLocations(IString scheme, IString auth, IMap map)
• [ ] unregisterLocations(IString scheme, IString auth)

These can be implemented after the java11 branch is merged, since no old functionality uses these methods. The reason for implementing them is to simplify the rascal-eclipse implementation and also to make sure everything in util::IDEServices of the Rascal standard library "works".