Create issue numbers and display when needed

[nickbe]

We should have proper issue numbers. Simply sequential is enough.

When I talk to someone over the phone referring to an issue like 'Just look at issue 24' would be really helpful.

Also I think issues should start from 1 in every project.

[satrun77]

Implementation started in branch develop-3.0. There is internal issues number starts from 1. Also, added project key. This is string of 3 characters unique to the project.

Example, if you have a project with key ABC, you can reference the issue number 1 as ABC-1

[nickbe]

Nice idea. This way there's always a clean way to reference project/ticket. I'll check this out. Have to do a clean installation of 3.0 first.