Default To MAC Configuration

[Azure-Agst]

First off, this is my first project messing with C# (I usually mess with C/C++) so please lmk if any code here is wonky or atypical and I'll change it.

This is hopefully the first PR of many as I really enjoy the idea behind this project and would love to help expand it further. The point of this PR was to pivot towards using MAC addresses as the default connection method.

• If an IP is detected on first connection, create a prompt that replaces the "Use MAC" button.
• Add "Automatically Convert IP to MAC" checkbox at the bottom of the main form.
• Modify Config.cs to allow for two new booleans to be saved. (Whether the user has been prompted and the checkbox value.)

[gabehxd]

Thanks for the PR, would you mind checking if older config files migrate correctly and don't get wiped from the new variables.

[Azure-Agst]

Using the code from your commit, it seems to load an "old" config file just fine, and overwrites with the new variables upon close as expected.

[gabehxd]

Looks all good to me