Make pre-set configuration files available through args

[euyniy]

Currently, there are two common OpenArm configurations:

• Pedestal-mounted: motor zero positions are defined with the arms hanging down in the neutral position.
• Cell-mounted: motor zero positions are defined when the arms are placed in jigs.

Also, on the control side, lower gains are useful for debugging and testing, while in certain cases stiffer gain settings are more desirable.

These are all valid and common scenarios, but they currently require different configurations. Could we make these behaviors configurable through arguments instead of relying on config overrides?