[bash/pangram] Create mentoring.md for pangram in the Bash track

[titanofold]

[SleeplessByte]

@titanofold I know it's been a while, but are you interested in applying or responding to Victor's comments so we can get this merged? If not, that's perfectly fine too of course.

[IsaacG]

@titanofold If you want to work on the above changes, let us know and we can reopen this! In the meantime, I'll close this out.