Provide ability to configure the location of the config JSON

[Jackie Gleason]

At work they blow away our user folder every night so I need to configure the location of the config file. I don't see anything in the docs that suggest this is supported.

I would like to store my config in a location other than \AppData\Local\Sqlectron\Config

[Michael Bøcker-Larsen]

I'd like to have one per project basis. E.g if .sqlectron.json exist in the current directory it will read that.

[Matthew Peveler]

Done in #116