Add an argument toterraform_validate to runterraform init before runningterraform validate.

Originally posted by@eytanhanig in#203 (comment)

Notes fo contributors:

• --hook-config support example
• K/V that passed to--hook-config support example

Additionally toforce-init option, we can useterraform providers and runterraform init if necessary, automatically. See this comment for more details -#299 (comment)