Provide a way for users to moderate custom blocks

Currently the content moderation and workflow modules allow site builder to apply a workflow to block types. But there is no moderated view to view those blocks in the workflow

Testing Steps

1. Enable content moderation and workflow
2. Configure workflow to work on any block type
3. Go to custom block library
4. Verify Moderated blocks tab
5. Create a block leaving in draft
6. Go to Moderated blocks page
7. Verify you see the block

Original Post

Similar to #2902187: Provide a way for users to moderate content → , we need to allow users to moderate block_content entities after #2820848: Make BlockContent entities publishable → .

This is currently postponed on:
#2862041: Provide useful Views filters for Content Moderation State fields →
#2902187: Provide a way for users to moderate content →
#2820848: Make BlockContent entities publishable →

Here's how the UI looks: