CAOM2.4: Observation Mode, CAOM version

[dr-rodriguez]

Some other wishlist items for CAOM v2.4 at the observation level:
An observation mode tag. While observation.type can get us some information about the type of observation, we sometimes need to provide more details and this observation.mode can be used to further refine that.

We need some way to track which CAOM version produced the xml. Something like observation.caom_version could be used to store this value. While Plane.provenance has tags related to version numbers, those refer to the files themselves rather than the generated xml. This would be useful while developing code to ensure that the xml files we are looking at come from the right code version.

[pdowler]

Please create model enhancement issues in /opencadc/caom2; I have already created an issue for the metadata versioning and I think there is a separate issue for improving the instrument model which I think would benefit from a comment about observing mode.

[yeunga]

Added enhancement suggestion on observing mode to opencadc/CAOM#11