Configure servos in YAML

[matthew-reynolds]

🚀 Feature Request

In order to work with generic servos, we need to have additional configuration when we specify the servo in the YAML file. This likely includes optional values for min angle (default=0), max angle (default=180), and perhaps min PWM (default 0.4ms) and max PWM (default 2.4 ms) timing.

Note: These defaults match the defaults specified by the WPILib (Which match the configuration for the Hitec HS-322HD servo provided in the Kit of Parts in 2008). We should maintain these same defaults, so that the default behaviour in our package will match the default behaviour when using the standard WPILib.