Firefox support: wait MV3

Is your feature request related to a problem? Please describe.

Discontinued maintenance of firefox version as of version 2.0.0, which means that the latest version of firefox Furigana Maker will be 1.6.1, which will keep the default addition of furigana functionality for X.

The main reason for this is that firefox currently has poor MV3 support, Service Worker missing in firefox MV3, which causes me to have to use firefox MV2, which is too much different code and causes me to have to test both browsers.

It adds a lot of maintenance costs.

Describe the solution you'd like

I will try to add it again when firefox MV3 is fully supported.

Describe alternatives you've considered

No response

Additional context

No response

Validations

[X] Check if you're on the latest Furigana Maker version.
[X] Follow our Code of Conduct
[X] Check that there isn't already an issue that asks for the same feature to avoid creating a duplicate.
[X] I would like to implement this feature via a PR.

aiktb / FuriganaMaker