supported releases by extensions

[ljleb]

Something I think may be useful for extensions would be to communicate to the webui whether it supports the currently running version.

I see multiple ways of achieving this:

• put a supported-releases.txt at the root of extensions directory tree to list all supported webui versions (ideally using semver, so we can write i.e. v1 and automatically support patch and minor changes)
• add a method supports_version to the extension script that returns a bool. one problem with this is hijacking code will hijack regardless of the return value here
• use install.py and i.e. throw if the version is not supported

That's the main ideas I could think of so far. I'm creating this discussion to see if there's any interest in designing a common interface for extensions regarding the support of different webui releases.

Practical use for this would include facilitating webui/extensions updates and disabling out of date extensions, among other perks regarding compatibility automation.

IIUC, by default, if no such mechanism is implemented by an extension, it should be assumed that it supports the newest webui release. An alternative would be to say that it supports only the oldest webui release (i.e. v1.0.0-pre).