Add support for unused, gosimple, and staticcheck

[alexkohler]

Description

The key for the message const tickerTime is unused (U1000) is null, issue not saved
The key for the message func handleTLSConnWithLogging is unused (U1000) is null, issue not saved
The key for the message printf-style function with dynamic first argument and no further arguments should use print-style function instead (SA1006) is null, issue not saved
The key for the message identical expressions on the left and right side of the '!=' operator (SA4000) is null, issue not saved
The key for the message unsigned values are never < 0 (SA4003) is null, issue not saved

I think adding checks for unused, gosimple, and staticcheck would be really valuable, as they're all pretty powerful linters. Staticcheck and gosimple's error messages are outlined here: https://staticcheck.io/docs/staticcheck#overview and https://staticcheck.io/docs/gosimple

[thibaultfalque]

Hello @alexkohler,

I will add checks.

Thanks for your feedback.