Create banner warning users that v2 website is not finished

[maxachis]

Context

At the moment, users could, however improbably, come to our new v2 website and think it's our main website. Maybe we should let them know that it's not ready?

Requirements

• Create a toast v2 web page with the following warning:

This is the v2 version of the PDAP search, and is still under development! Data here is unreliable, and created accounts are deleted on a regular basis. For the current version, head to https://data-sources.pdap.io

Tests

• No tests needed

Docs

• No documentation needed

Open questions

• None

[maxachis]

@joshuagraber Does this seem to make sense to you as something we should do?

[josh-chamberlain]

I updated the copy a bit. I think we can use the lovely toast infrastructure for this.