Get rid of ConstraintSetSyntax for PromiseTypeSyntax

BodyTypeSyntax and PromiseTypeSyntax need different check functions.
Get rid of ConstraintSetSyntax for BodyTypeSyntax
Change type of CONTROL_BODIES from PromiseTypeSyntax to BodyTypeSyntax, because its a body
For action bodies, check that log_repaired is accompanied by log_string

Close #789 (Enterprise)
First-pass cleanup of execd LocalExec
Constify cf-execd-runner
First-pass cleanup execd CompareResult
First-pass cleanup execd Dialogue
First-pass cleanup execd MailResult
First-pass cleanup execd FileChecksum
Move FileChecksum to hashes.h, add unit test