Add Mastodon / Other Social Media profile link for speaker bios

[craigmaloney]

Currently there is a field for Twitter in the speaker bio. It would be nice for me to add my Mastodon profile to my speaker bio as well (I don't currently have a Twitter account).

Mastodon profiles are in the format @craigmaloney@octodon.social, but even a field that takes a https link would suffice (eg: https://octodon.social/@craigmaloney). Making this a link would also allow other platforms like Friendica, Diasora, et al.

Thanks!