add WiFi provider with Network Manager backend

[Davemane42]

Adds a new WiFi provider for managing wireless networks through elephant.

Features:

• Scan, connect, disconnect, and forget WiFi networks
• Password support via #password in the search bar (i really dont know how to do it otherwise, maybe just open another terminal like the AUR provider)
• Configurable subtext format with {lock}, {status}, {signal}, {frequency}, {security} in the config
• Configurable message_time and error_time for status/error feedback duration
• Backend interface — modular design to support multiple backends
  (only support Network Manager with nmcli right now)

I also have a PR for Walker so it support the socket message like the Bluetooth provider
abenz1267/walker#702

Obfuscated the SSID name for the screenshot

I dont really know how the nix stuff or github action stuff work so i didnt touch them.

[Davemane42]

changed the way passwords are inputed.

it opens a terminal window and obfuscate the character with dots (can be hidden in the config)

will probably add different ways based on the backend or authentication agent

[abenz1267]

Walker has a --password flag for passwords. Can that be used?

[Davemane42]

@abenz1267

With the latest commit I made, I have some "preset" for different dmenu style launchers and Walker is the one by default.
In the config you can set a custom command and if all of these fail it's gonna use the terminal

https://github.com/abenz1267/elephant/pull/231/changes#diff-2ff8432f7062b8effa3b8211b7b481934ad8f996d9e4018e535a27a31b65004dR19