HA ESPHome integration inactive device folder

**Describe the problem you have/What new integration you would like**
A location to store inactive devices within the Home Assistant integration.

**Please describe your use case for this integration and alternatives you've tried:**
I've got some devices that I use on occasion, for example a Sonoff S20 that I use during holidays, Christmas lights, etc. I would like to be able to store them in some area in the Home Assistant integration, so they'll be (temporarily) excluded from updates but will show up when becoming active.

Currently I've taken some precautions so I can "easily" access the devices when I re-introduce them into my netwerk, without losing it's functionality. I've:
- renamed the device to the MAC-address of the device (name = esphome-{MACaddress without the colon's}, friendly_name = {MACaddress with colon's}),
- ~~removed the OTA password~~,
- ~~removed the API-key~~,
- removed the web-server login,
- changed the hostname in the HA integration
- renamed the YAML-file in the ESPHome folder matching the device's name.

The config reset of the config and thus functionality of the device is kept intact. The devices will show up at the bottom of my list, so that's nice. I'm afraid a new binary will be created whenever a new ESPHome-version is released or something else has changed; using unnecessary computing power.

I could create a folder in the ESPHome folder and store the devices at that location. Whenever I re-introduce the device I could copy all the files in the folder I've created back to the main ESPHome folder and move all unavailable configs back whenever the re-introduced device comes back online; but if I could make them "inactive" with a few clicks of a button that would be nice.

**Additional context**
Removing all safety features like passwords, login and keys should allow the device to show up in Home Assistant, should allow me to upload a new configuration with ease and should allow me to access it through the web if all this fails.

The payload names only the ESPHome folder and device YAML files, with no repository entry point or test. Start by locating how the Home Assistant integration discovers ESPHome configurations; done would be a defined, reversible way to mark devices inactive, exclude them from updates, and restore them when active.

Written by the indexing model from the issue text.