Documentation, Please!

**Is your feature request related to a problem? Please describe.**
There's zero documentation on configuration, nor any explanation about what this library does to existing framework/infrastructure. We've had to implement a myriad of hacks and work-arounds (a lot of clearing the headers that Symfony is setting for gods know why - any API server already handles CORS) to even get the basic TUS server running in CodeIgniter 3 on a production implementation and can only use the 'file' cache and storage systems because there's NO CONFIGURATION DOCUMENTATION whatsoever! How do we pass Redis host/port/auth info to TUS? How do we pass S3 keys and secrets to TUS? No clue, since there's no documentation on it! And yet TUS-PHP advertises having these features. Without documentation, they're inaccessible.

**Describe the solution you'd like**
A couple new documentation sections on 1) how to configure your Redis, S3, etc. would be a bare minimum solution but 2) the extra mile would also be explaining what the server is going to try to do for you, apparently it assumes that it's going to be a standalone server with no fully configured API host in front of it, and sets a myriad of headers your server probably already sends, duplicating headers which make a browser essentially reject TUS responses.

**Describe alternatives you've considered**
The alternative is you forcing me to pore through your entire library to understand how it works rather than just dropping in my configs and running - are you trying to force more users of the project to become contributors? Because that's how it feels. We use libraries to save ourselves time and effort, not to be coerced into becoming contributors!

**Additional context**
Given how fast PHP has been changing and updating in the last few years, I'm disappointed to see how slowly this library is coming along.