feature: local aur

[lokrok]

to extend off #4 I have a lot of local PKGBUILDs I use that aren't on the AUR or are edits. For stable version ones, this is fine since I have to edit them anyway, but I have to just constantly check if there are updates for git PKGBUILDs. It would be really nice, convenient, and a big weight off my back from digging through soylang helpers if there was a way to define a "local aur" to check and update from. something as simple as a folder to throw PKGBUILDs of your own in and have it sync with them would be nice.

thanks