chore: Rename Projects to Templates (#880)

Customer feedback indicated projects was a confusing name.
After querying the team internally, it seemed unanimous
that it is indeed a confusing name.

Here's for a lil less confusion @ashmeer7 🥂

coderd/database/migrations/000003_workspaces.up.sql

@@ -5,7 +5,7 @@ CREATE TABLE workspaces (
     -- Use ON DELETE RESTRICT so that we can cleanup external workspace
     -- resources first.
     owner_id uuid NOT NULL REFERENCES users (id) ON DELETE RESTRICT,
-    project_id uuid NOT NULL REFERENCES projects (id) ON DELETE RESTRICT,
+    template_id uuid NOT NULL REFERENCES templates (id) ON DELETE RESTRICT,
     deleted boolean NOT NULL DEFAULT FALSE,
     name varchar(64) NOT NULL,
     PRIMARY KEY (id)