[8.x] Document RateLimited and WithoutOverlapping Job Middleware

[paras-malhotra]

Document the 2 new job middleware: RateLimited (laravel/framework#34829) and WithoutOverlapping (laravel/framework#34794) to be released tomorrow on Laravel 8.11.

There was a section on rate limiting using Redis::throttle and Redis::funnel. This section is removed because:

1. The RateLimitedWithRedis class does the same thing as Redis::throttle. The Redis::throttle is also already documented in the job middleware section.
2. The Redis::funnel method is now moved to the job middleware section as an example to limit concurrency.

This way, all 3 types of middleware (rate limiting, preventing overlapping and concurrency limiting) are documented together in the job middleware section.

[sansebi]

WithoutOverlapping works like a charm! 👍
I run into a dead end with my CACHE_DRIVER being set to file

Call to undefined method Illuminate\Cache\FileStore::lock()

Would be nice to extend the docs that it only works for specific cache drivers.

[driesvints]

@sansebi can you send in a PR for that?

[paras-malhotra]

Thanks @sansebi, I sent a PR to document this: #6520