tty: add hasColors function

[BridgeAR]

This adds a small wrapper around the getColorDepth function to check
if the stream supports at least a specific amount of colors. This is
convenient as the other API is not as straight forward and most use
cases likely only want to know if a specific amount of colors is
supported or not.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines