add support for proxying images and files always via keystone express server, no matter local or s3, and add security access control extension hook

[sunnymoon]

Implemented proxied mode (it was referred to in the documentation and examples as creating a server route on express, but it didn't for s3 case) in s3 as well as leaving the same "static express mapping" as before for local storage mode.
Implemented an access Control hook extension point to validate access to either local or s3 assets with proxied mode
Fix the documentation to conform to "serverRoute" always (instead of distinguishing between s3 or local kinds).
Still feel the code could be further improved by:

1. Not allowing "generateUrl" to be implemented on the case of "proxied" mode (serverRoute.path defined)
2. Check for "overlaps" between the "serverRoute.path" and other express middlewares at startup and warning the devs about it
3. Implement the pathPrefix option (correctly on s3) on local storage kind (and mkdir accordingly at startup)
4. Check for "signed" vs "serverRoute.path" vs "acl" options and warn devs appropriately

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 79620ca:

Sandbox	Source
@keystone-6/sandbox	Configuration

[sunnymoon]

Is anyone looking at PRs? How could I help further ?

[pmatrola-linkare]

I need this pull request to use in my project

[dcousens]

Hi @sunnymoon, I am reviewing pull requests, but I haven't had a chance to test this particular pull request yet.

If anyone else is up to help review and test, that will be appreciated.

[sunnymoon]

Hello Daniel: Thanks for getting back. In terms of the review what or whom would you suggest could do the PR analysis... Someone from our Team/Company? Best regards José A sexta, 1/03/2024, 12:18, Daniel Cousens ***@***.***> escreveu:

…

Hi @sunnymoon <https://github.com/sunnymoon>, I am reviewing pull requests, but I haven't had a chance to test this particular pull request yet. If anyone else is up to help review and test, that will be appreciated. — Reply to this email directly, view it on GitHub <#9001 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABBHUKAI3RUR2SYGG7TPWM3YWBWXXAVCNFSM6AAAAABCVKKCB6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSNZTGA4DQOJRGI> . You are receiving this because you were mentioned.Message ID: ***@***.***>