Create gateway API key modal

[PavelJankoski]

Summary

References #6697

Changes

• Added new button in gateway overview subheader.
• New modal when clicking on the newly added button.
• Cover new scenario with e2e tests.

Testing

Steps

1. Login to console.
2. Go to gateways section.
3. Select a gateway.
4. New + API key button should be present in the subheader of the gateway overview.
5. New modal should be opened.
6. Try to create API key.

Results

Notes for Reviewers

I added scrollbar in the rights form field if there are two many options and/or small screen (this may be subject to change in the future)

Checklist

• Scope: The referenced issue is addressed, there are no unrelated changes.
• Compatibility: The changes are backwards compatible with existing API, storage, configuration and CLI, according to the compatibility commitments in README.md for the chosen target branch.
• Documentation: Relevant documentation is added or updated.
• Testing: The steps/process to test this feature are clearly explained including testing for regressions.
• Infrastructure: If infrastructural changes (e.g., new RPC, configuration) are needed, a separate issue is created in the infrastructural repositories.
• Changelog: Significant features, behavior changes, deprecations and fixes are added to CHANGELOG.md.
• Commits: Commit messages follow guidelines in CONTRIBUTING.md, there are no fixup commits left.

[KrishnaIyer]

This is really nice @PavelJankoski! Good stuff

[ryaplots]

Great job! Here are some comments