Related issues

Related to STU-921.

Proposed Changes

• introduce deeplink handling for base64-enocoded blueprints
• extract out createBlueprintFromData and applyPreferredVersions logic
• move main window focus logic
• rename IPC Events
• add related unit tests

ℹ️ Please note that we will be adjusting the UI/UX once the designs are ready. This PR only adds raw support for base64-encoded blueprints in deeplinks.

Testing Instructions

1. Check out the PR branch and build the app with npm install && npm start.
2. Try out the following deeplinks and confirm they do what they are supposed to do. 🙂

Broken blueprint:

wpcom-local-dev://add-site?blueprint=invalid-base64!!!

• an error message in a dialog should show up

Working blueprint:

wpcom-local-dev://add-site?blueprint=eyJwcmVmZXJyZWRWZXJzaW9ucyI6eyJwaHAiOiI4LjMiLCJ3cCI6ImxhdGVzdCJ9LCJzdGVwcyI6W3sic3RlcCI6Imluc3RhbGxUaGVtZSIsInRoZW1lRGF0YSI6eyJyZXNvdXJjZSI6IndvcmRwcmVzcy5vcmcvdGhlbWVzIiwic2x1ZyI6ImFzdHJhIn0sIm9wdGlvbnMiOnsiYWN0aXZhdGUiOnRydWV9fSx7InN0ZXAiOiJpbnN0YWxsUGx1Z2luIiwicGx1Z2luRGF0YSI6eyJyZXNvdXJjZSI6IndvcmRwcmVzcy5vcmcvcGx1Z2lucyIsInNsdWciOiJ3b3JkcHJlc3Mtc2VvIn0sIm9wdGlvbnMiOnsiYWN0aXZhdGUiOnRydWV9fV19

• should land right on the Add a site step
• if you click the Add site button the site with the related blueprint should create itself

Test for regressions:

1. Follow the testing steps in Rahul's (already-merged) PR: Blueprints: Add a deeplink to create a new site from the blueprint URL #1989.
2. Everything should be working well.

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?