Rename WIP merge requests to Draft
## Problem to solve
WIP limits are being added to issue boards https://gitlab.com/gitlab-org/gitlab/issues/11403 which creates a naming collision with [WIP (Work In Progress) merge requests](https://docs.gitlab.com/ee/user/project/merge_requests/work_in_progress_merge_requests.html).
Furthermore, WIP merge requests are frequently used to mean "this MR is a draft, please don't merge" even though they are complete and ready for review.
## Further details
The acronym "WIP" is not commonplace in software community worldwide and even less so for non-english speakers. "Draft" is a more inclusive and self-explanatory term.
## Proposal
1. Rename the feature **Draft**
1. Reword title subtext in MR edit mode from:
“Start the title with WIP: to prevent a Work In Progress merge request from being merged before it's ready.”
to
“Start the title with `Draft:` or `WIP:` to prevent a merge request that is a work in progress from being merged before it's ready.”
“Remove the [`Draft`|`WIP`] prefix from the title to allow this merge request to be merged when it's ready.”
1. Add support for `Draft:`, `[Draft]`, `(Draft)`, or `Draft - ` **case insensitive** prefixes in:
1. The merge request title.
1. Commit messages targeting the merge request’s source branch.
1. Reword the MR widget when in draft state:

While `WIP` deprecation is active, we should support both `WIP` and `Draft` prefixes for MRs and commit messages
## Future work
1. Rename the `WIP` filter in the merge request list. We would need to change it in a way that doesn't break old URLs that still use it: https://gitlab.com/gitlab-org/gitlab/-/issues/227414
1. Rename or add a new `/draft` alias to the `/wip` quick action: https://gitlab.com/gitlab-org/gitlab/-/issues/227415
## Links / references
issue