Dvc: colorama: standardize and apply output message colors

[jorgeorpinel]

I just recently discovered we're using colorama when reviewing https://github.com/iterative/dvc/pull/2765/files but haven't really noticed it much in most DVC output.

Current use I can see now:

• colorama.Fore.BLUE is used for some URLs. I like this, should check it's ALL URLs.
• RED and GREEN are used in the updater. This seems OK.
• BLUE, RED, and YELLOW in the logger.
• CYAN (called blue) is used for the man.dvc.org URLs here and here. Not sure we need this per the first bullet (BLUE).
• MAGENTA for 2 "HINT" messages here and here. Should check it's used in all such hints, and that other "SOMETHING:" messages always have heir own colors.
• There's this colorize function in dvc/dvc/utils/__init__.py:
  https://github.com/iterative/dvc/blob/cfc442e932701af5ef94b94d8b70b8bd117fc6f8/dvc/utils/__init__.py#L349-L359
  but doesn't seem to be in use. Use it or lose it. only used in boxify. Use it more (or remove it).
• Finally, PR #2765 may introduce BLUE for sample commands in the output (those surrounded with back ticks for example. Should we apply this everywhere? (Also "dynamic" commands, printed inside single quotes'`.)

[efiop]

Good catch @jorgeorpinel !

There's this colorize function in dvc/dvc/utils/init.py

It is used in boxify https://github.com/iterative/dvc/blob/master/dvc/utils/__init__.py#L389 .

[jorgeorpinel]

Thanks. Should probably use it more or remove it?

[efiop]

@jorgeorpinel Hm, why remove it? But yeah, could definitely use it more :)

[jorgeorpinel]

Idk. It only knows 4 colors rn, and the resulting syntax is not that easy to read, at least in boxify:

        "{border}{space}{border}\n".format(
            border=colorize(chars["vertical"], color=border_color),
            space=chars["empty"] * box_size_horizontal,

vs. something like

"{blue}text{nc}\n".format(blue=colorama.Fore.BLUE...