CMDP: Drop Description from Metrics Payload

This MR drops the metric description from CMDP metric payload frames. Especially with high-throughput (DQM) scenarios this is obstructive and also does not help much in general. Order of items is changed to have value first.

Descriptions should go into the READMEs of satellites producing them.

Discussion at also remove the unit? @hanno.perrey said it might be helpful to keep it.

I would also claim that this closes #18 (closed) since we then just say: documentation needs to be consulted, or just subscribe to the firehose and filter yourself.