[ENHANCEMENTS] Disable Certain Features (e.g. uptime monitor)

[overcuriousity]

Option to disable certain features which are not needed
I found a discussion which suggests that we should be able to opt-out certain features and agree to that.
The user RainrZufall points out in this thread that the "uptime monitor" causes his NAS not going to sleep as it is constantly pinged.
My setup has some LXC containers which are resolved by domain, but just provide an API in a subpath - which causes the uptime monitor showing a yellow result as there is nothing found on the root dir of that domain.

Implementation Suggestion

• Provide option on a per-entry basis in the HTTP-Proxy GUI to disable the uptime monitor (switch or checkbox)
• Provide a commandline-flag to opt out of the uptime monitor or the Global Area Network (as I have no use for the ZeroTier-Stuff and don´t want to see it on the UI)
• consistantly offer commandline-flags or config option to disable any features (and hide them from the GUI)

[tobychui]

@overcuriousity The issue with the uptime monitor is that it is kinda required for active fail-over switching in the upstream load balancer. Without (or with disabled) load balancer on a certain rule will force that dpcore (the module that handle "actual" load balancing and routing) to only be able to use passive fail-over detection. I will see what I came up with later.