Adds a new API for web apps to request the sharing of the extension's contact list to avoid having to maintain duplicate lists. This is a read-only sharing of non-sensitive data.

If the web app user wants to update the contact list, they still need to do it inside the extension so it remains the single source of truth. It was not worth expanding this to enable editing of contacts from outside of extension as the security considerations and implementation ROI was not worth it.

• npm run extension
• update browser with the local extension build from previous step
• open up eCash Chat (see email for link), login via extension
• scroll down and click the temporary get contact list from Cashtab button

• approve this request in extension and observe the successful rendering of contacts in the web app