Add support for Identity Server Configuration

### Your use case

#### What would you like to do?
Add support for Identity Server Configuration. Currently the ElementX client does not have this feature supported where in comparison it does exist within the older Element client. I would also like the option to configure the Identity Server to "None".

#### Why would you like to do it?
I would like to be able to configure the Identity Server which ElementX will use or to set it to "None".

#### How would you like to achieve it?
Could the section with this feature of the older Element codebase be integrated into the ElementX codebase?

### Have you considered any alternatives?

Current alternative to have this feature supported would be to use the older Element Client which currently supports it.

### Additional context

_No response_

### Are you willing to provide a PR?

No