User + Connection ID refactoring

[prawnsalad]

Currently user IDs are just the user names. Connections do not have an ID but the name is being used as an identifier.

To bring everything inline and easier to store in databases I propose we do the following:

• Users and connections have both an ID and Name field.
• Internally we use the ID fields for identifying instances, never the Name field.
• We can then provide ways to change the Name field with suitable restrictions while the ID fields stay the same.

Baring in mind the different datastore backends that may be possible, I think that using standard UUIDs v4 would be the best ID format to use. Most database engines support these in some form and reduces friction in generating unique IDs in each datastore implementation.

Thoughts before I go ahead with this?

[DanielOaks]

Hmm, I could see this happening, yeah. We'll need to keep the names unique anyways so that people can login using them, but if we use IDs as the primary identifier we can change users' names without worrying too much.

One interesting thing to consider, if we allow users to change their own usernames, we won't be able to use their username as the username send via IDENT (if we support ident). For big installations at least. Since nets will ban based on the reported ident username, we can't just let users change that at a whim.