Due to calling the Colorize function with the full string instead of the
format string, plan/apply logs which include resource instance keys or
IDs which happen to match color formatting would be rendered
incorrectly.
This commit fixes this by only colorizing the known-safe format string.
We also add full test coverage for the UI hook, although only one of the
hooks is tested for this color bugfix due to verbosity of the test.
We also add the bold coloring to the provisioner output prefix, which
seems to have been an oversight.
Move the code which renders Terraform hook callbacks as UI into the
views package, backed by a views.View instead of a cli.Ui. Update test
setup accordingly.
To allow commands to control this hook, we add a hooks member on the
backend Operation struct. This supersedes the hooks in the Terraform
context, which is not directly controlled by the command logic.
This commit should not change how Terraform works, and is refactoring in
preparation for more changes which move UI code out of the backend.
Alisdair McDiarmid