View History of All Group Imports - Frontend

What does this MR do and why?

This MR implements history of group imports as described in #285577 (closed)

Following changes were made compared to designs in issue:

• "Source group" is not a link, because we're not exposing ATM url of host instance. So we know that source group was, for example foo/bar but have no idea on which host

• We do not expose via API initiator of request so we do not have corresponding column

• No filtering functionality - not supported by API

• Added pagination missing on designs

Screenshots or screen recordings

New_Group___GitLab

How to set up and validate locally

• Enable feature bulk_import via Feature.enable(:bulk_import) (should be enabled by default)
• (we are assuming you have default GDK setup with private group Commit451 available)
• Impersonate to any non-admin user
• Open "New group" -> Import (/groups/new)
• Use https://gitlab.com as source instance and GeK1Nis4j-SY1X4sqE5c as personal access token (this token is from separate user on GitLab instance with 0 real data available, so we do not expose any security risks here)
• Try to specify Commit451 as import target name
• Observe validation error

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.