Install Joplin Server without docker in Proxmox

Development
14

@kcrawford This guide is great, but I think it needs to be updated or rewritten.

2 things:

  • yarn is now used in the project
  • a section on how to upgrade the server would be nice, even if it only mentions to just repeat steps 5 and 6 with a git pull beforehand

I have now added a how-to tag. We can also move it to the #lounge category, if you want.