VDEMS WEBSITE CHANGE REQUIRED FOR LOCAL MASTER SERVER v2

The existing website currently uses an HTTPS local server URL such as:
https://192.168.29.220:3000

v2 uses:
http://192.168.29.220:3000

Update the VDEMS master-server connection code/settings validation so HTTP
private-IP URLs are accepted.

For fetch requests from the public HTTPS VDEMS site to the private LAN server,
current Chrome Local Network Access may show a one-time permission prompt.
The user must choose Allow.

Keep CORS restricted to the VDEMS Firebase Hosting origins already listed in
server-config.json.
