Add new namespace scoped Interceptor CRD introduced by Triggers v0.22

[AlanGreene]

Changes

Add list page and plumbing for the new namespace scoped Interceptor resource which was introduced in the most recent Triggers release v0.22.

Use the common CustomResourceDefinition container for the details page.

/kind feature

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Docs included if any changes are user facing
• Tests included if any functionality added or changed
• Follows the commit message standard
• Meets the Tekton contributor standards (including
  functionality, content, code)
• Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• Release notes block below has been updated with any user facing changes (new features, significant UI changes, API changes, bug fixes, changes requiring upgrade notices or deprecation warnings)
• Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

Add new pages for the namespace scoped Interceptor resource introduced in Triggers v0.22

[AlanGreene]

Wait until #2599 is merged
/hold

[AlanGreene]

/hold cancel

[briangleeson]

/lgtm

[tekton-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: briangleeson

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [briangleeson]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment