[ENHANCEMENTS] Variables and Aliasing

[deathbybandaid]

Is your feature request related to a problem? Please describe.
N/A

Describe the solution you'd like
I'd like to be able to use some sort of {{external_ip}} and other custom variables/aliases.

Describe alternatives you've considered
N/A

Additional context
On my current haproxy configuration I have any request by my external IP address 403.

Additionally, some built-in variables could also be handy, such as a tool that keeps track of external IP (for those of us using dynamic IP).

Adding a config page for custom variables/aliases to be set would also be handy.

For instance, I have a couple of digitalocean droplets with wireguard that forward traffic to my pfsense as interfaces. It would be nice to set a custom variable {{digitalocean_droplet_ext_ip}} that I could call in other places in zoraxy.

Or say you want a webpage accessible from a remote office with an external IP address, you could set {{remote_office_ext_ip}} and add that to a whitelist for a specific ACL.