Add Type to int/float attributes.

* Optionally attach the type of integer and floating point attributes to the attributes, this allows restricting a int/float to specific width.
  - Currently this allows suffixing int/float constant with type [this might be revised in future].
  - Default to i64 and f32 if not specified.
* For index types the APInt width used is 64.
* Change callers to request a specific attribute type.
* Store iN type with APInt of width N.
* This change does not handle the folding of constants of different types (e.g., doing int type promotions to support constant folding i3 and i32), and instead restricts the constant folding to only operate on the same types.

PiperOrigin-RevId: 221722699