Fix current setting URI

[FlowingSPDG]

Hello, Thank you for develop awesome tool for vMix! We're using this tool in production.

I would like you to fix Save setting URL, which uses beta URI currently. I'm using this for my personal vMix assist utility(https://github.com/FlowingSPDG/vmix-utility). that means URI might be different from current one.

Also I've added focus for saveURL element for better copy n paste operation.

Thank you!