add an 'issue labeling' section to contributing (#844)
add an 'issue labeling' section to contributing (#844)

* add an 'issue labeling' section to contributing

first crack at creating an issue labeling guide/explanation.

* comments for nancy

* more review updates

* Wordsmithed new labels section

Consider adding definitions to the 3 main label types (lines 50-53) if you think there's any possibility of ambiguity (probably pretty clear as is though). I bulleted them and the priority levels to make them easier to see at a glance.

* small cleanup of the wordsmithing

* Final few edits to labeling section

Good to go after these minor tweaks, @coffeepac

yenicapotediaz/k2,leahnp/k2,alejandroEsc/k2,yenicapotediaz/k2,samsung-cnct/k2,samsung-cnct/k2,leahnp/k2,samsung-cnct/kraken-lib,alejandroEsc/k2,samsung-cnct/kraken-lib,samsung-cnct/kraken-lib