DM XML: DataType parsing

[cecille]

We have parsing for cluster elements from the data model XML files currently implemented in the matter testing python tools area, but we don't parse out the data types. Data Types would be good to have as well. No specific tests yet, just building out the infrastructure.

There's a start here:
project-chip/connectedhomeip#37904

Still needs

• unit tests
• tests that the errors are properly propagated
• handling for bitmaps where a field spans more than 1 bit - suggest maybe just having multiple members like MemberA MemberB for the different bits. These currently show up as errors.