Define lists of LAVA callback metadata keys
Define lists of LAVA callback metadata keys

Define in app.models the lists of LAVA callback metadata keys that are
accepted and mandatory for each type of callback (boot and test).
This can then be used to validate the metadata from LAVA callbacks.

Signed-off-by: Guillaume Tucker <e7e20b7c30f19d4ca6b81319ef81bf200369d137@collabora.com>

kernelci/kernelci-backend,kernelci/kernelci-backend