[clangd] Add symbol tags in SymbolInformation, WorkspaceSymbol, CallHierarchyItem and TypeHierarchyItem (#170103)
Introduce support for symbol tags in `SymbolInformation`, `WorkspaceSymbol`, `CallHierarchyItem`, and `TypeHierarchyItem`.
As part of this change:
- Calculation of the symbol tags Overrides and Implements
- Calculation of symbol tags during the AST creation and embedding them in `Symbol`.
- Minor change on struct Symbol to minimize paddings and thus reducing memory consumption.
Continuation of PR #167536
Fixes #180843