Support icon color

[wodesuck]

Implement #928 #1520. Now you can add the third column in ~/.config/lf/icons to set icon colors, fallback to filename color in ~/.config/lf/colors if icon color is not specified.

Example:

*.styl              00;38;2;141;193;73
*.sass              00;38;2;245;83;133
*.scss              00;38;2;245;83;133
*.htm               00;38;2;227;76;38
*.html              00;38;2;227;76;38

Also implement #992. You can remove icons by writting only one column in ~/.config/lf/icons, for example:

ln             # LINK
or             # ORPHAN
ow             # OTHER_WRITABLE
di             # DIR
ex              # EXEC, disable excutable file icon, select icon by filename

[joelim-work]

Thanks for the patch, overall looks good. The only downside to this approach is that you can't specify icon colors using environment variables, but it's probably not worth doing anyway.

In addition, I suggest you should:

1. Change the unit tests for readPairs to test readArrays instead.
2. Update the documentation for icons.
3. Add some examples (commented out) to the etc/icons.example config file.

[joelim-work]

I think you might want to rename this variable:

Suggested change

	pairs = append(pairs, arr)
	arrs = append(arrs, arr)

[wodesuck]

@joelim-work Updated, check again pls. 🙏

[joelim-work]

Looks good, thanks once again for the changes.

[joelim-work]

OPTIONAL: This is just an idea, maybe it might be worth moving this into a separate file (e.g. icons_colored.example). But either way is OK for me.

[wodesuck]

I think that is a good idea too. Already moved.

[gokcehan]

Thank you very much @wodesuck for the patch and @joelim-work for the review. There is some conflict in this patch after #1644 is merged, and I wasn't sure how to resolve them. Can you please update the patch one more time? Sorry for the inconvenience as we have been holding many feature patches for a while due to the new release.

[wodesuck]

@gokcehan Conflict resolved.

[joelim-work]

I have closed #928 and #1520 since they are now addressed by this PR. I will leave #992 open though, although it's possible to delete the entry for ex, I'm not sure whether there's still a way to keep it but prioritize it lower than file extensions.