docs: finish pages marked as TODO

[brenoepics]

Is your feature request related to a problem? Please describe.

There are several pages in the documentation that contain TODOs. These need to be completed to provide comprehensive information to the users.

Details

The following pages contain TODOs:

1. docs/src/essential/error-handling.md - More information about error handling in AT4J is needed.
2. docs/src/azure-reference/datacenter-list.md - A list of Azure datacenters and their locations is required.
3. docs/src/advanced/caching.md - More information about caching for AT4J is needed.

Tasks

• Complete the error handling page with relevant information.
• Create a list of Azure datacenters and their locations.
• Complete the caching page with relevant information.