Support Manifest V3

[Garethp]

As annoying as it is, Google is forcing Manifest V3 down my throat. So let's get onto supporting that. Here's what we need

• - Upgrade our libraries so we're not working in the stone age
• - Support both browser.action and browser.browserAction
• - Move over to the new API's for contextMenu
• - Add loading resources from new paths that are now relative to our built JS files
• - (Optional) Look into why Firefox can't read Kanji radicals on manifest v3
• - Support a new Audio playing mechanism for Manifest v3
• - Copy our build system from the Vortex Chrome plugin to support building both v2 and v3 simultaneously
• - Test Anki integration

The main reason that Firefox's V3 Support investigation is optional is that I really really don't want to migrate over until Firefox either sorts out its V3 implementation or forces me to. Denying all permissions to an extension and then not telling the user when that extension needs permissions is the most useless decision that I can think of.