Jump to channel switcher

[richrd]

This adds a search box to the sidebar, that can be used to filter and navigate channels. It can be toggled with alt+j.

This is how it looks on the default theme:

Fixes #1454

[richrd]

I would say this pretty much ready as it is, except in an ideal world we'd use ctrl+k for the shoctcut. That's what slack, discord, mattermost and others use for this feature.
Problem is that ctrl+k is used for color selector, do we want to change that or just go with alt+j or some other less standard shortcut?

EDIT: If we end up changing shortcuts this should be considered at the same time #2442

[Mikaela]

Do you have any idea how much TheLounge users use colours or formatting? I think IRC users mostly don't use colours and even people using them may be open to changing to another shortcut as they would likely be used to ctrl+k of the other apps.

[dgw]

Any rebinding of Ctrl-K away from colors should be very carefully considered. It's the de facto standard color shortcut. (For the record, I'm strongly against doing so.)

[Mikaela]

Where is it the de-facto standard color shortcut? I cannot remember coming across it in other context than channel switching.

[dgw]

Granted it's an unscientific sampling, but nearly every client I've ever installed used Ctrl/Cmd+K for colors (mIRC, KVIrc, TL). Search for "irc color ctrl-k" and see for yourself how much newbie documentation references it, e.g. https://en.wikichip.org/wiki/irc/colors and (currently not loading for me) http://www.ircbeginner.com/ircinfo/colors.html

[xPaw]

Looks like our component style compiling puts jump-to styles above our style.css which is probably not a good idea. Can we tweak the order somehow?

Besides that, this PR seems good to go for me.

[xPaw]

Add the keybind to help window.

[xPaw]

Squash and merge 👍