Add on_rc_switch trigger

[escoand]

Description:

This adds the missing trigger for RCSwitch.

remote_receiver:
  ...
  on_rc_switch:
    - logger.log:
        format: "on_rc_switch: %i %llu"
        args: [x.protocol, x.code]

Related issue (if applicable): fixes esphome/feature-requests#550

Pull request in esphome-docs with documentation (if applicable): esphome/esphome-docs#

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[brandond]

LGTM