feat: show peer count in menu and tray tooltip

[sutartmelson]

Addressing feature request from #1312. The peer count is retrieved whenever the menu is opened (all systems) and whenever the user hovers over the tray (Windows/macOS).

Fetching the information this way means the displayed peer count isn't always up to date. Depending on the OS, the number shown usually reflects the number of peers at the time of the previous menu open event.

If electron updates its API to allow dynamically editing menu labels, this feature could be improved.

In tray:

In menu:

Tray and menu when IPFS isn't running:

[lidel]

I really want to avoid constant polling, even if it is once a minute.

Would it be possible to change this PR to remove polling?

I was looking at tray APIs while working on #1762 and perhaps we could refresh cached peer count via this event:

• https://www.electronjs.org/docs/api/tray#event-mouse-move-macos-windows

The above API is not available on Linux, but it should not be an issue in practice: the value is not real-time anyway, so we could simply display the last cached value + refresh cache asynchronously every time the menu is rendered (in addition to mouse-move event), so it still works on Linux.

@sutartmelson lmk your thoughts on this.

[sutartmelson]

@lidel, Great idea, if polling is to be avoided (which is understandable), displaying the last cached value and fetching a new one at menu open is a good compromise. The displayed peer count isn't perfectly up to date, but I don't think it needs to be. I also updated the PR description accordingly. Hopefully this last change is a step in the right direction. Thanks!

[lidel]

I rebased this PR and fixed pluralization of peerCount label in the menu.

Hoped to include it in the release but was unable to make it work on Linux at all: turns out when "app indicator" tray backend is used on Linux, the click events are ignored, so we have no way to trigger peerCount refresh before menu is displayed.

TODO

• figure out what to do on Linux (find a way to trigger this, disable, or poll)
• we seem to have two "Peers" items now – one on the top, and then "Peers" link for opening Peers screen in webui. I think we want to deduplicate this (eg. remove "Peers" and make one with count clickable and open Peers screen win webui)

[AlexxNica]

@lidel, how is this showing on Linux atm? If it's already disabled I think we can just leave it as is for Linux until we have a fix so we're not holding this issue just for that.

For the second to-do item, I'm with you that only one "Peers" should remain.