feat: add username and password login (#418)

* feat: add username and password login

* fix: make sure cookie is not empty

* chore: go mod tidy

* fix: prevent local config from influencing tests

* fix: small cleanup on error handling

* fix: remove unnecessary trim

api/contract/cli.yml

@@ -129,6 +129,8 @@ paths:
     $ref: "./openapi/src/svc/invocable-scripts/paths/scripts_scriptID.yml"
   /api/v2/scripts/{scriptID}/invoke:
     $ref: "./overrides/paths/scripts_scriptID_invoke.yml"
+  /api/v2/signin:
+    $ref: "./openapi/src/common/paths/signin.yml"
 components:
   parameters:
     TraceSpan: