TAGS: Freely definable simple tags per project

[nickbe]

We could use an independend and freely definable tag group per project. This could be useful to assign an area in which the issue belongs, or for software a certain release that is planned or the name of a sprint.

Also It should be possible to assign multiple tag values to an issue. They should be displayed seperately from our status/type/resolve tags.

These free tags could be simply entered in a comma seperated text field. So all can have the same color. Regarding editing they should be treated like issue name/description -> so if the status has changed then users can not change those tags anymore. devs/managers can change those tags if they currently have non-read access to the issue.

When entering an issue then these tags (if available for this project) should (all in the same color) be selectable the same way as for example our status tags.

In some projects the manager might have defined some issue scopes here and they should be used when entereing a ticket. In other projects those project tags might be used for planned software versions.

So I also suggest one new system config setting:

New tickets: [ Must have at least one additional project tag ]
[ Can have one or more additional project tags ]
[ May be entered without additional project tags ]