Put camera platform labels in dict

This is set to merge into !538 (merged) to make it easy to review as it contains all of those commits. I suggest we approve and merge !538 (merged) first, then set this to merge to master.

From #474 (closed), add a "message" item to the optics_config dictionaries to label the Upright camera platform automatically, so that parts and renders are always synchronised.

This also suggests adding labels to the C270 and B0196 camera platforms. The text positioning looks a little odd, because 'upright' has risers and descenders, but 'C270' has no descenders so appears not to be central.

Standard:

Upright:

C270:

B0196:

closes #474 (closed)