Add a search bar to find SSH keys (privately or publicly accessible) easier in project settings deploy keys
### Problem to solve
As a project maintainer on a gitlab instance (hosted on your own server), when you have to add a private SSH key that is existing on the global instance to your current project (in Settings > Repository > Deploy keys > Tab Privately accessible deploy keys), it's hard to find the one you want when you have a lot of keys.
See, I have 19 pages :

**If it's possible, It will be better if we had a search bar to search keys by name and find it easier.**
### Intended users
Maintainers and owners
### User experience goal
The user should be able to find and enable SSH keys easier
### Proposal
Add a search bar here :

### Permissions and Security
* [x] Add expected impact to Maintainer (40) members
* [x] Add expected impact to Owner (50) members
issue