Footer text: source code version

[niconoe]

• Make sure it stays "Pterois source code version"
• ... And point to the engine repository
• and shows a commit number, but also tags/releases if available

[damianooldoni]

That's indeed a good idea. Notice that now it is a broken link, as expected after creating a new repo with the old name, early-alert-webapp.

[niconoe]

Thanks @damianooldoni. All fixed now!