Code Insights: [FE] Create a first implementation of capture group creation UI page

Created by: vovakulikov

Close part of https://github.com/sourcegraph/sourcegraph/issues/28026

Series of PR

1. This one creates main layouts for capture group creation UI
2. Create live preview chart for capture group
3. Improve live preview chart and connect it to gql api

Context

This PR adds a first implementation of the creation UI page for the capture group insight. A few things to highlight:

• We extract MonacoQuery editor from search-based insight creation UI
• Common styles for building a common creation UI layout page have been extracted to insights shared component

Knowing problems that would be solved in further PRs

• Live preview block hasn't been connected
• Checklist wasn't included in this PR (this will be done in this PR https://github.com/sourcegraph/sourcegraph/pull/28362)
• The page itself hasn't been connected to the dashboard page.
• Form autofocus first invalid input doesn't work with Monaco query field. https://github.com/sourcegraph/sourcegraph/issues/28653