Add BitBucketServerImport project filtering

What does this MR do?

This MR adds filtering functionality to BitBucket Server imports. It adds a simple input field that passes entered input to BitBucketServer as a query string. Please note that Bitbucket Server and Bitbucket Cloud are 2 different things. Bitbucket Cloud API is far more advanced, having filtering API, while Bitbucket API only allows to pass in name as a param.

More details in https://gitlab.com/gitlab-org/gitlab-ce/issues/51260

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios.
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Performance and testing

N/A

Security

N/A