update services

[butlerx]

https://www.redbrick.dcu.ie/help/services/ needs to be updated user vhost is now the default aswell hg is being replaced by git by @AlexKraak

• [x] virtual machines arn't offered anymore
• [x] username.redbrick.dcu.ie is now the defualt for hosting redbrick.dcu.ie/~username can be removed
• [x] Hg is replaced with git
• [x] webmail isnt mentioned or linked too
• [ ] list of all user services
• [x] new services that need to be mentioned
  • [x] mastodon
  • [x] hackmd
  • [x] hastebin