Add Github Action to Deploy to Web Stores

[ColdSauce]

(disclaimer, I removed some typescript code since I didn't see it was necessary but I just noticed that you're working on a migration to typescript. If you'd like me to, I can rebase my commits and remove all of those changes, just let me know!)

Hey @timbru31, we made a Github action to make it easier to deploy to each of the web stores. Saw you were thinking of doing something like this with #18. This PR integrates your extension to our Github action so you can deploy directly from the Github UI.

Currently supporting Chrome, Firefox, Edge, and Opera (Safari support coming soon too)

The only thing you would need to create is a SUBMIT_KEYS GitHub repository secret.

This secret is a JSON, with the schema defined here.

Here's a sample json blob of the keys you'll need to add to the Github secret:

{
  "$schema": "https://raw.githubusercontent.com/plasmo-corp/bpp/v1/keys.schema.json",
  "chrome": {
    "clientId": "123",
    "clientSecret": "456",
    "refreshToken": "789",
    "extId": "abcd"
  },
  "firefox": {
    "apiKey": "123",
    "apiSecret": "abcd",
    "extId": "foobar"
  }
}

You can find instructions on how to get those keys in the schema, or if you use vscode, the schema should provide hint/intelisense when hovering over the json properties. If you need any help in setting up the keys, feel free to @ me.

Otherwise, if this doesn't seem necessary, feel free to close the PR!