UI: Add example modal to policy form

[malinac02]

Add example modal to policy form

Description:

• In create policy, clicking "example template" renders a modal with the corresponding policy example.
  • Modal is also available when editing an already-existing policy
• Modal is not available when creating a policy is already a modal. When this is the case, the policy example is still available via another tab (for example, creating a policy through Access/Entities)
• Beneath the policy example, there is a link to more information about that policy type
  • This link is available under the policy example both when it is displayed in the modal and when it is displayed as a tab

Images:
Before:

After:

[hellobontempo]

Nice work!! Some minor cleanup comments, and we just need to add the third policy sample!

[github-actions]

Build Results:
All builds succeeded! ✅

[github-actions]

CI Results:
All Go tests succeeded! ✅

[hellobontempo]

Really great work on this! Let's hold of merging until someone else has reviewed, but looks great to me! ⭐

[Monkeychip]

Looks great! Nice work 🚢