Description

This PR:

• Replaces "Create a delegation" and "Redeem a delegation" guides with new "Execute on a smart account's behalf" guide, refactored from previous Delegation quickstart. Adds redemption options (smart account vs. EOA) as tabs.
• Restructures delegation guides to fall under "Delegation" category.
• Makes edits throughout Delegation concept page, and updates it to include delegation types and execution modes. Also moves Caveat enforcers concept page as subpage under this category.
• Minor updates and fixes to related content.
• Updates redirects and links.

Issue(s) fixed

Fixes #2241
Fixes #2239

Preview

https://metamask-docs-qzssfxb78-consensys-ddffed67.vercel.app/delegation-toolkit/development/concepts/delegation/

Checklist

Complete this checklist before merging your PR:

• If this PR contains a major change to the documentation content, I have added an entry to the top of the "What's new?" page.
• The proposed changes have been reviewed and approved by a member of the documentation team.