Proposal: add support for Wear OS

Similarly to #1422 (closed) and artwork!17 (comment 278941262) support an optional field in the metadata that indicates support for Wear OS. By default, this field is not provided and indicates that no info is available on support for Wear OS.

WearOS: no
WearOS: yes
WearOS: notification

A value of yes refers to apps that have functionality on the wearable device, like a full app, at least more than only notifications that are shown. Icon that can be used is watch An example app is Telegram

A value of notification refers to apps which notifications are passed on to the wearable device. This depends mostly on the type of notification an app is giving. The app has no special presence on the wearable device. The notification is simply passed on by the smartphone's OS to the wearable device, and sometimes also back, e.g. via a mark as read. Icon that can be used is An example app is Etar

For no value or a value of no, nothing is shown.

For apps marked with yes or notification, this info can be shown in the F-Droid website, F-Droid client apps and repo search. Additionally, user could also search for this info.