refactor(datatypes): improve typing

[OutSquareCapital]

This PR improve the expressions::datatypes::{DataType, DataTypeParam} type safety, with the kwargs argument in DataType::build narrowed from object to a new dedicated TypedDict in the _typing module, and a narrowed this property on DataTypeParam

[OutSquareCapital]

Unfortunately this couldn't be narrowed in the other way, i.e DataType::expressions, since there's a lot of unsafe attributes acces that would require logic change instead of pure typing changes.

I determined the values simply by dummy typing it as list[float] at first, and then adjusting depending on the errors:

sqlglot\generator.py:5042: error: List item 0 has incompatible type "Literal | Neg"; expected "float"  [list-item]
sqlglot\dialects\dialect.py:1731: error: List item 0 has incompatible type "DataTypeParam"; expected "float"  [list-item]
sqlglot\optimizer\simplify.py:20: error: Library stubs not installed for "dateutil.relativedelta"  [import-untyped]

I also knew that struct types use exp::ColumnDef