[CLI] css font-family utilities for ease of use and clarity

[NathanWalker]

A sore spot for quite a long time is trying to get the font-family combination correct for iOS/Android.
For a custom font such as barlow-bold.ttf the css needs to be:

font-family: Barlow, barlow-bold;

Getting this correct is sometimes incredibly frustrating for custom fonts.

Proposal: Potentially add a convenient cli command which prints out exactly what css is needed for any given font:

$ ns font /path/to/barlow-bold.ttf

Here's the CSS to use:

font-family: Barlow, barlow-bold;

Also make sure you place the font inside the `fonts` folder at root of your app.

Benefit: Save ton of time debugging why custom fonts aren't working.

[rigor789]

I agree with @NathanaelA since custom fonts are in fonts/ folder - we should just list all fonts in the folder.

$ ns fonts

Found Custom Fonts:
-------------------
barlow-bold.ttf    ->    font-family: Barlow, barlow-bold;
fontawesome.ttf    ->    font-family: FontAwesome, fontawesome;

Though, I guess listing system fonts could also be useful, perhaps with a flag to reduce noise?

[NathanWalker]

I like a flag to list all if desired but default would print custom fonts in fonts folder only as long as mentions that’s the output it’s printing by default clearly and mention the flag which can be added to list all maybe / Although listing all is usually runtime related since iOS and Android only upon running can output the full list to my knowledge.

[rigor789]

Active RFC: #21