Upgrading to Manifest v3

[rumpeltux]

TabFS is currently using manifest v2, which will go away eventually and there are some limitations in it.

e.g. I was thinking of adding routes for /frames to be able to get HTML not only of the main page body, but also of any frames included in a given page. However this doesn’t work with iframes showing data: urls in v2 and is only supported in v3.

On the other hand the watches/ functionality is not compatible with v3, as dynamic code execution via executeScript or eval is no longer supported (see here) and it will go away January 2024. Not sure what the best way around this is. In the current "bundle your own extension" install mechanism, it’s not a big deal to included custom snippets manually, but it's certainly just a little more painful than the existing variants. A js emulator is probably overkill / infeasible?

Maybe there need to be two extensions for the time being. v2 for the watches functionality (while it lasts) and v3 for everything else.