Added Telegram, Mastodon and Matrix channels for GALPon.org

[capri99]

Not sure if "Matrix" Font Awesome icon exits. If not, this commit could break anything?

[Daniel-at-github]

I don't know if this is info is helpful, Fontawesome didn't have it, but forkawesome have it

[pabloarias]

Miguel, from GALPon, asked me to change Twitter link to Mastodon: https://mastodon.gal/@galpon

How can we achieve this?

[alexhermida]

Oh! didn't realise about this PR 🤦🏽‍♂️ @pabloarias @capri99 I can approve this and the @pabloarias you can open a new one updating twitter from your fork if you want.

[pabloarias]

I think the problem is the icon. There is no Mastodon icon in this Font Awesome version.

Maybe we can change icons font to Fork Awesome, like @Daniel-at-github says.

Volunteers?

[alexhermida]

Yes, but as long this doesn't break anything, I'm happy to merge it and also to remove Twitter in another PR 😄

Updating to fork-awesome would be a independent one, I'm not aware if it would break anything. 👀