Climate Thermostat Component additional actions for deadband/overrun

**Describe the problem you have/What new integration you would like**

It would be great to have the option to declare additional actions for `deadband` and `overrun`.
Example names for the actions: `cool_deadband_action`, `cool_overrun_action`, `heat_deadband_action`, `heat_overrun_action`.
The above actions should work the same way as other standard actions in the component, for example, `heat_action`, `cool_action`.

**Please describe your use case for this integration and alternatives you've tried:**

I'm realizing an automated Heat/Air conditioning system with centralized HVAC. For my project I've used Curtain modules to open/close air throttles separately for each room. I'm currently using `cover.open` and `cover.close` actions for `heat_action` and `cool_action`. I'd like to be able to set throttles not only in open and closed states but set the open state to 30-50% while `overrun` happens. Example setting which I'd achieve:
- cooling deadband: throttle open 100%
- cooling on: throttle open 100%
- cooling idle: throttle open 50%
- cooling overrun: throttle open 30%
- cooling off: throttle open 0%

**Additional context**

These additional actions should be viable for other heating and cooling systems where we can set middle states for specific hardware.

Start by locating the Climate Thermostat Component and its existing heat_action and cool_action handling. Compare how deadband and overrun states are represented, then determine the configuration and tests needed for the four requested actions; done means each action supports the described intermediate throttle states.

Written by the indexing model from the issue text.