Settings page for chrome-extension

[AdityaPimpalkar]

Current behavior

For now we have a single textbox to change server url for user who will self host

This textbox is currently on the same page as the oauth screen.

Expected behavior

We should have a separate page with server url textbox as editable and another textbox with chrome-extension url as non editable.

This could be a follow up of #5260 or could be kept as a separate page for now