docs: install instructions for Debian and RHEL 9.

[ravecat-dev]

No description provided.

[AutisticShark]

Have you actually tried RHEL 9 instructions on the server? That seems missed a lot of key configs.

[ravecat-dev]

I don't know what you mean by lots of key configs are missing, isn't it nearly the same as ur Ubuntu config?

but I will install the panel on another AlmaLinux server later, and I will detail the process further in the future and will ensure the config doc is more detailed.

[ravecat-dev]

oops, wrong click

[AutisticShark]

For RHEL 9, you will need to use nginx.org and Redis Lab's Linux mirror since the one in the default repo is always one major version behind. For Debian 12, you will also need to replace the usage of the default package with up to date 3rd party repo because we will drop PHP 8.2 support once PHP 8.4 comes out.

[ravecat-dev]

oke, didn't know this project did not have minor version compatibility, I will modify the pr when I have time.

[AutisticShark]

I saw you have maintainer edit enabled on this PR, I will do some tweaks and it should be ready to merge.