Add support for testing other common SDP files

[andrewbonney]

At present given the user-base this is likely to target SMPTE standards including:

• ST.2110-22
• ST.2110-31
• ST.2022-6

However, it would be useful to include a mode which permits more general purpose SDP validation without the specifics from the standards.

[garethsb]

+1, it's about time we did this

[garethsb]

Also need ST 2110-40 checks for format specific parameters DID_SDID (which unlike other params can appear multiple times) and VPID_Code.

[garethsb]

Summarizing...

• ST 2110-22 tests, focused on video/jxsv is being added by Bcp 006 01 rbg #21. Ultimately that may need to be refactored to support other compression formats being used with ST 2110-22. However, those new tests for video/jxsv currently only test the required RFC 9134 format-specific parameters (packetmode), they don't validate any of the optional params.
• ST 2110-40 video/smpte291 currently has no fmtp tests.
• ST 2022-8 video/SMPTE2022-6 is also currently skipped.
• ST 2110-31 audio/AM824 testing may also be incomplete?