Feat: Enable type attributes

[Schottkyc137]

Closes #184

Implementation details:
Introduces a new return type AttrResolveResult which is either a type (for attributes such as 'subtype, 'element) or a value (for most other attributes such as 'high, 'low, ...)

Based on this attribute the name can be resolved correctly and a'subtype'high will resolve to the correct type while a'subtype as an expression yields an error

[Schottkyc137]

Note: Also related to #147 since a type_mark can now simply be parsed as name (as opposed to a selected_name) as resolve_name now correctly resolves type of a name. The only "problematic" thing is the diagnostic handling in the AnalyzeContext (EvalResult vs AnalyzeResult).