Incremental additions to platform documentation (#8898)

### Changes 🏗️

Adding incremental documentation based on YouTube series: 
- How to Submit an Agent to the AutoGPT Marketplace
- How to Download and Import an Agent from the AutoGPT Marketplace
(Local Hosting)
- Creating a Basic AI Agent with AutoGPT
- How to Edit an Agent in AutoGPT
- How to Delete an Agent in AutoGPT

---------

Co-authored-by: Bently <tomnoon9@gmail.com>
Co-authored-by: Nicholas Tindle <nicholas.tindle@agpt.co>

docs/mkdocs.yml

@@ -8,7 +8,13 @@ nav:
   - Home: index.md
 
   - The AutoGPT Platform 🆕: 
-    - Getting Started: platform/getting-started.md
+    - Getting Started: 
+        - Setup AutoGPT (Local-Host): platform/getting-started.md
+        - Edit an Agent: platform/edit-agent.md
+        - Delete an Agent: platform/delete-agent.md
+        - Download & Import and Agent: platform/download-agent-from-marketplace-local.md 
+        - Create a Basic Agent: platform/create-basic-agent.md
+        - Submit an Agent to the Marketplace: platform/submit-agent-to-marketplace.md   
     - Advanced Setup: platform/advanced_setup.md
     - Agent Blocks: platform/agent-blocks.md
     - Build your own Blocks: platform/new_blocks.md
@@ -156,7 +162,6 @@ plugins:
   - git-revision-date-localized:
       enable_creation_date: true
 
-
 extra:
   social:
     - icon: fontawesome/brands/github