Add custom name to private networks/custom RPCs

[wbt]

What problem are you trying to solve?
I'm frequently changing between private networks and want to see at a glance which network I'm on, ideally with some human-readable name, instead of just "Private Network:"

Why should only large public testnets be nameable?

Describe the solution you'd like
I'd like the ability to assign a custom name to RPCs, similar to how I can assign a custom name to an account number.
Also, in the popup where I'm asked to approve a transaction being sent, I'd like to be able to see which network I'm on when sending the transaction. In the upper right, there's a box containing a question mark in a circle with the words "Custom RPC" but clicking on that circle (or anywhere else in that box) does nothing, nor does hovering over it show a tooltip with the URL.

I would like for the box to say "Development Server" or "Test Server" or whatever other name I want to affiliate with the RPC URL, and on hover see a tooltip that shows me it's using RPC https://12.34.56.78:9001 or something like that.

[wbt]

An implementation of the UI from @bdresser's September 12 comment on issue #5134 would likely address at least part of this Issue; there may be some residual parts regarding the tooltip on hover to show the URL. It looks like there's progress being made there; thanks!

[wbt]

This appears fixed in version 4.17.1, likely in PR 5134.

[filips123]

Pull request #5134 only adds chainId field, but network will still be displayed as URL in menu. Is it possible to change it?

[wbt]

@filips123 What version are you using? When I set a custom name for the network (see field in this screenshot or later ones) that custom name shows up in the upper right and in the drop-down that appears when I click on the network selector.

[filips123]

@wbt It is OK! I change wrong field.