Rename caching to performance

[lsl]

After moving Cloudflare and Jetpack promos to the caching screen, rename caching to performance

• Re-title the caching page
• Redirect /caching to /performance
• Load the caching page at the new /performance route

Hard blocked by:

• Move Cloud flare and Jetpack promos to Caching settings #98713
• Remove Settings > Performance menu item jetpack#41145

[github-actions]

OpenAI suggested the following labels for this issue:

• [Feature Group] Site Performance: The issue pertains to renaming the caching feature, which is directly related to the overall performance of the site.
• [Feature] Caching: The issue primarily involves the caching functionality and its renaming to align better with performance.
• [Feature] Jetpack Connection Errors: Since Jetpack is mentioned in the context of promos being moved, it could be referenced in the context of caching and performance.

[lsl]

I don't think this is needed now. (designs changed, we just dropped the cloudflare promo outright)

[lsl]

Misunderstanding, we're still waiting on an update from CF.

[lsl]

I don't think we'll need this anymore. pfsHM7-1tK-p2