Load events configuration from custom file

[Blooym]

Changes

Instead of forcing users to mount a custom nginx.conf file to modify the events configuration, we should instead allow them to use a /custom/events.conf file to modify it, as is standard for other advanced parts of NPMs configuration. It also reverts the default worker_connections amount to NGINX's default to prevent duplicate key issues if a user wants to set a custom worker_connections amount.

Rationale

I was consistently running into issues when using NPM as I was unable to modify my worker_connections amount without some hacky workarounds, so I wanted to make it as easy as changing other parts of the configuration.

Additional Information

Let me know if anything in this PR needs adjusting, I am by no means an NGINX expert and just wanted to upstream some of my local changes. If this is unwanted, feel free to just close the PR.

Linked Issues

Fixes #1435, #1912, #2388

[nginxproxymanagerci[bot]]

This is an automated message from CI:

Docker Image for build 1 is available on DockerHub as jc21/nginx-proxy-manager:github-pr-2444

Note: ensure you backup your NPM instance before testing this PR image! Especially if this PR contains database changes.

[msycn]

Wow ,you are my hero ! Thanks for your idea ,wish will pull request soon