Add Notification for Users to verify domain is app.anchorprotocol.com

Many users on the forums and discord have reported having funds drained due to scam websites. In addition to this scam websites have been posting google adds to get people to click on their domain. These websites pull Anchor front end and disguise themselves as the official protocol. Once users interact with these sites their funds are drained with no way of recovery. A simple notification or pop up on the screen of the web app would help users to ensure they are on the correct site and save a lot of trouble for novice users who will end up loosing their funds without it. This has been implemented on many dapps as scammers are getting sophisticated with their attacks. Anchor would benefit from the same.

Here is an example on olympus's website:

https://app.olympusdao.finance/#/dashboard

I can do this on my time if nobody else is interested and close issue once its ready for pull.

Start with the web app described in the issue and compare the requested warning with the Olympus example at https://app.olympusdao.finance/#/dashboard. Define the notification's placement and wording so users can verify app.anchorprotocol.com, then verify that it is visible to users on the web app.

Written by the indexing model from the issue text.