Update Theme: Tab Numbers

[philmard]

Added z-index to the tab numbers, for no overlap with the "X" close-button.

Also added Preferences to the theme:

1. Set Custom Color for Tab Numbers (w/ Hex Code)
2. Change Size of Tab Numbers
3. Bold or Normal text

[philmard]

Hello @mr-cheff ! I see my theme got updated, but I had also added a preferences.json file, which I don't see included in the https://zen-browser.github.io/theme-store/themes.json.

I would appreciate it if you could also add that, so that the users of the theme can do these extra stuff:

1. Set Custom Color for Tab Numbers (w/ Hex Code)
2. Change Size of Tab Numbers
3. Bold or Normal text

Thank you in advance!

[mauro-balades]

Absolutely! But if you could do a PR to save me some time, I'd be very grateful

[philmard]

here it is!

#852