feat: Update CLI to handle managed variables (#6220)

* 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: create

* unit tests: create templates with variables

* Use last variables

* Fix

* Fix

* Fix

* Push tests

* fix: variable is required if Default is nil

* WIP

* Redact sensitive values

* Fixes

* Fixes

* Fix: arg description

* Fix

* Variable param

* Fix: gen

* Fix

* Fix: goldens

docs/cli/coder_templates_create.md

@@ -14,6 +14,8 @@ coder templates create [name] [flags]
   -h, --help                          help for create
       --parameter-file string         Specify a file path with parameter values.
       --provisioner-tag stringArray   Specify a set of tags to target provisioner daemons.
+      --variable stringArray          Specify a set of values for Terraform-managed variables.
+      --variables-file string         Specify a file path with values for Terraform-managed variables.
   -y, --yes                           Bypass prompts
 ```