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

coderd/database/queries/templateversionvariables.sql

@@ -0,0 +1,26 @@
+-- name: InsertTemplateVersionVariable :one
+INSERT INTO
+    template_version_variables (
+        template_version_id,
+        name,
+        description,
+        type,
+        value,
+        default_value,
+        required,
+        sensitive
+    )
+VALUES
+    (
+        $1,
+        $2,
+        $3,
+        $4,
+        $5,
+        $6,
+        $7,
+        $8
+    ) RETURNING *;
+
+-- name: GetTemplateVersionVariables :many
+SELECT * FROM template_version_variables WHERE template_version_id = $1;