refactor: make paths to icons direct

Merge branch 'master' of https://github.com/zws-im/browser-extension

docs: add Chrome Web Store badge

refactor: use #808080 as loading color

fix: remove broken browser action image, fixes #1

chore: fix publish scripts

chore: use PNPX for Chrome Web Store

chore: install dev dependencies

chore: add addons linter for Gecko

chore: add deploy scripts

refactor: use browser-specific variable for events

refactor: split extensions into Chromium and Gecko

docs: remove developer key because Chrome doesn't support it

docs: add me as a developer in the manifest

feat: support all Gecko based browsers