This is a bigger refactor of vmount to clean it up and plug some holes
in functionality.
The changes include:
- Fixing/simplifying the test command.
- Changing the dependencies of the input and output classes to just the
parameter list.
- Adding a separate topic to publish gimbal v1 commands to avoid
polluting the vehicle_command topic.
- Removing outdated comments and author lists.
- Extracting the gimbal v2 "in control" notion outside into control_data
rather than only the v2 input.