Fix output bug in kolide_profiles

[directionless]

Apple's profiles command does not correctly output stdout in one very narrow case. Work around this by writing output to a temp file.

Additionally, restrict the commands allowed on profiles to read only commands. This is enforced by a new option to the GetConstraints helper.

[blaedj]

LGTM, tested out locally and can confirm that it produces output as expected for queries that do not return values on commits prior to this.

I did have one question on the tests