Make output messages more user friendly and informative

[reaganmcf]

Make stdout easier to read and friendly. Some ideas:

• When exec command succeeds, some sort of Successfully ran. Monitoring for file changes... message to stdout in some color
• When lightmon starts, some sort green(?) message showing it started

[alayshahh]

I remember one issue we were having was trying to handle different colored outputs for different scenarios. We experimented withe ANSII escape codes but it didn't really work. I came across this comment thread here which might help if we decide to look at this again or just as reference for the future

In reply to a question about changing colors for output

A common standard for this are the ANSI escape codes. You could e.g. use a crate such as ansi-parser to parse them in your print function. Then you can use a crate such as owo-colors to stylize your println! invocations.