feat: Expose managed variables via API (#6134)

* WIP

* hcl

* useManagedVariables

* fix

* Fix

* Fix

* fix

* go:build

* Fix

* fix: bool flag

* Insert template variables

* API

* fix

* Expose via API

* More wiring

* CLI for testing purposes

* WIP

* Delete FIXME

* planVars

* WIP

* WIP

* UserVariableValues

* no dry run

* Dry run

* Done FIXME

* Fix

* Fix: CLI

* Fix: migration

* API tests

* Test info

* Tests

* More tests

* fix: lint

* Fix: authz

* Address PR comments

* Fix

* fix

* fix

cli/testdata/coder_templates_push_--help.golden

@@ -13,6 +13,7 @@ Flags:
                                       automatically generated if not provided.
       --parameter-file string         Specify a file path with parameter values.
       --provisioner-tag stringArray   Specify a set of tags to target provisioner daemons.
+      --values-file string            Specify a file path with values for managed variables.
   -y, --yes                           Bypass prompts
 
 Global Flags: