[Core] Add support for observation parameters

[alexrobin]

We can implement parameters as DataBlocks described with a SWE Common schema (like obs results)

[alexrobin]

One way to do this is to associate the main Datastream containing the observation results (e.g. imagery) to one or more other Datastreams that contain the parameters (e.g. sampling information such as sensor position and orientation, fov, etc.).

Parameters could still be expanded on-demand when requested as part of an observation object, while still be accessible as a separate datastream, thus providing maximum flexibility and backward compatibility with what we are already doing (e.g. UAV video + telemetry).