Add On Off Command Support to Fan Group on FanLinc

[krkeegan]

Proposed change

Adds support for on and off commands for the fanlinc.

Expands on PR #399.

Additional information

• This PR fixes or closes issue: fixes can't send messages to FanLinc group 2 #398

Checklist

• The code change is tested and works locally.
• Local tests pass.

[krkeegan]

Multigroup devices need additional code to handle the on off commands. It isn't clear if this can be abstracted to a single code base. Currently, fan_linc and outlet look very similar. Keypadlincs also have multigroup support, but they use a different command to achieve this.

Likely if another device similar to the fan_linc and outlet are added, we should move these multigroup commands to their own abstract class.