feat: add Docker, Drone CI, and k8s deployment manifests

- Dockerfile for Python 3.12 FastAPI app
- Drone CI pipeline to build and push to internal registry
- Kubernetes manifests (Deployment, Service, Secret, Namespace)
- ArgoCD Application for GitOps deployment
- Kustomize base configuration

.drone.yml

@@ -0,0 +1,22 @@
+kind: pipeline
+type: docker
+name: build-and-push
+
+trigger:
+  branch:
+    - main
+    - develop
+  event:
+    - push
+
+steps:
+  - name: build-and-push
+    image: plugins/docker
+    settings:
+      repo: 192.168.68.11:30500/invest-api
+      registry: 192.168.68.11:30500
+      insecure: true
+      tags:
+        - ${DRONE_COMMIT_SHA:0:8}
+        - latest
+      dockerfile: Dockerfile