Construct-typing

- adapted stubs to `construct` v2.10.64
- renamed "TContainerBase" to "TContainerMixin"
- changed "swapped" to "reverse" in TStruct and TBitStruct

- added covariant for `ParsedType` and contravariant for `BuildTypes` (thanks to ad1217)
- renamed `cst.TStructField` to `cst.sfield`
- renamed `cst.TUnionField` to `cst.ufield`
- fixed typing error from pylance in the constructor of `TEnum` and `TFlagsEnum`

- updated to construct v2.10.61
- fixed some typing issues
- strip trailing new lines in documentation of "TStructField"
- adding also values that are not part of the dataclass to the "TContainer" while parsing
- added setting "add_offsets" and __getattr__ to TStruct
- corrected pinning to specific version

Initial version