Allow Single Project Export - offline backup that can be re-imported

Copied from JRACLOUD-67824 – Ability to move Single Project to New Instance:

Update 8 March 2024

I am updating the Summary and Description of this ticket based on the discussion in the comments. Please note that single project transfer to another site is now possible for Jira Software and Jira Work Management projects using the Cloud-to-cloud migration tool.

As a Jira admin whose Jira data is potentially subject to retention and other types of regulations, I need to make an exported copy of a Jira space before I delete it so that if the data within becomes needed down the road, it can be restored as it was WITHOUT needing to remain archived or otherwise hidden but ultimately active on the instance".

Keeping a project, particularly a team-managed project, around in your instance means dealing with all of the 'cruft' of that instance. This is particularly painful with custom fields, as TMP's often create fields of the same name in their projects, which Jira overall handles poorly in the UI. Thus, deleting the project entirely is really the only way to keep your instance clean.

Some organizations have retention and other regulatory requirements which make keeping the projects in some form a necessity. We do not know what data we might need down the road due to audit or legal issues, and so deleting the projects entirely creates risk we cannot tolerate.

Having an exported copy of the project resolves this - we can still delete it, but if someone comes up with a need for the data, we can always re-import it. As it stands...

The issue export is not enough since it does not include things like attachments or comments, which are critical pieces of context.
The full instance export is too much. Ours is more than 200Gb, making it quite frustrating to work with if for no other reason than its size.

Original summary: Allow Single Project Export

Original Description:

In order to move a project between two different instances, an user must export a whole XML backup from the source instance, and will only import one project in the target.

For huge instances, where there are over 400 projects, exporting a full XML backup may result in performance issues during the time it takes for the backup to complete, and as exporting all 400 projects is not necessary to only import one project, it would be good if it was possible to export only one single project to be imported into another instance.