[feature] enable editing of `conf.xml` for a given connection

[duncdrum]

To be fleshed out, but it would be a nice feature, if users could open the conf.xml that configures a server instance. e.g. via a more button on the connection properties menu.

If we can also initiate a restart, that would be quite a hoot.

For a start just having a read-only copy open in the editor window, would already be a great help.