This fleshes out ASTMethodOrConstructorDeclaration to abstract what can be abstracted, and align their grammar more closely

Grammar changes

• Merge ASTAnnotationMethodDeclaration into ASTMethodDeclaration. I don't see the point of having two separate nodes, the only API difference is that annotation methods may have a default value.
  • The removed node had no MethodDeclarator, or FormalParameters, which just introduced more nullability in the API
• Add an ASTBlock as a child of ASTConstructorDeclaration -> was just inconsistent
• Replace NameList with ThrowsList
• Remove MethodDeclarator, former children are direct children of the method declaration. This node just introduced inconsistencies (ConstructorDeclaration didn't have it) and an unnecessary level of nesting.
• Add many useful methods to ASTMethodOrConstructorDeclaration

API changes

• Add JavaNode#getEnclosingType, ASTCompilationUnit#{getPackageName, getTypeDeclarations}
• Rename ASTMethodDeclaration#getBlock to getBody, now shared by constructor declarations
• Rename ASTConstructorDeclaration#getParameterCount to getArity, now shared by method declarations

Internal changes

• Reimplement the name fetching routines of JavaRuleViolation so that they don't use the old symbol table anymore. That was completely unnecessary and the old symbol table is broken a bit more by this PR.

TODO on master

• Deprecate AbstractJavaRule#getDeclaringType (replaced by JavaNode#getEnclosingType)
  • Backport JavaNode#getEnclosingType to master
  • AbstractJavaRule#getDeclaringType is useless, it only cares for class or interface types, it returns a simple string, even though the enclosing type may be anonymous...
  • The new method returns the node instead, and is available everywhere
  • -> a12afd1
• 04e5619 Deprecate ASTMethodDeclaration#getMethodDeclarator - the methods "getFormalParameters()", "getMethodName()" should be used directly instead.
  • also add "getParameterCount()"/"getArity()" to ASTMethodDeclaration
  • introduce the new aliases for the other renamed methods on master and deprecate the old ones (like what was done for getFormalParameters)
    • ASTMethodDeclaration#getBlock -> getBody
    • ASTConstructorDeclaration#getParameterCount -> getArity