add inst-cli docker-compose override yamls

create a new sub-dir docker-compose/inst-cli/ and add
the docker compose overrides needed to work with inst-cli.

Test Plan:
- with a canvas docker setup, add ":inst-cli/docker-compose/selenium.override.yml"
  to your COMPOSE_FILE.
- run docker compose up -d
  - selenium-hub service will start
- run any rspec test with docker
  - test will run on the newly created selenium-hub service

Change-Id: I225fe59a7d2a8798762ba6f7def8c3dbbef46c56
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/312654
Reviewed-by: Michael Hargiss <mhargiss@instructure.com>
QA-Review: James Butters <jbutters@instructure.com>
Product-Review: James Butters <jbutters@instructure.com>
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>

inst-cli/docker-compose/mailcatcher.override.yml

@@ -0,0 +1,23 @@
+# to use this add docker-compose/mailcatcher.override.yml
+# to your COMPOSE_FILE var in .env
+
+version: '3.2'
+services:
+  mailcatcher:
+    image: instructure/mailcatcher
+    depends_on:
+      - canvas-web
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.mailcatcher-router1.service=mailcatcher-canvas-lms"
+      - "traefik.http.routers.mailcatcher-router1.entrypoints=web"
+      - "traefik.http.services.mailcatcher-canvas-lms.loadbalancer.server.port=8080"
+      - "traefik.tcp.routers.mailcatcher-router2.rule=HostSNI(`*`)"
+      - "traefik.tcp.routers.mailcatcher-router2.entrypoints=smtp"
+      - "traefik.tcp.routers.mailcatcher-router2.service=mailcatcher-canvas-lms-smtp"
+      - "traefik.tcp.services.mailcatcher-canvas-lms-smtp.loadbalancer.server.port=1025"
+
+networks:
+  default:
+    external: true
+    name: "inst_shared"

inst-cli/docker-compose/selenium.override.yml

@@ -0,0 +1,51 @@
+# to use this add docker-compose/selenium.override.yml
+# to your COMPOSE_FILE var in .env
+
+version: '3.2'
+services:
+
+## We list all of the different standalone containers as `selenium-hub` since Jenkins
+##  will use the actual hub + node configuration instead of a standalone for performance
+##  reasons. Listing all of them as selenium-hub saves a great deal of configuration issues
+
+## Chrome
+  selenium-hub:
+    image: selenium/standalone-chrome
+    # Use the seleniarm (not selenium) image on ARM architectures
+    # image: seleniarm/standalone-chromium
+    depends_on:
+      - canvas-web
+    environment:
+      SE_NODE_GRID_URL: selenium-hub:4444/wd/hub
+    init: true
+    ports:
+      - "5901:5900"
+
+## Firefox
+  # selenium-hub:
+  #   image: selenium/standalone-firefox
+  #   # Use the seleniarm (not selenium) image on ARM architectures
+  #   # image: seleniarm/standalone-firefox
+  #   depends_on:
+  #     - canvas-web
+  #   environment:
+  #     SE_NODE_GRID_URL: selenium-hub:4444/wd/hub
+  #   init: true
+  #   ports:
+  #     - "5900:5900"
+
+## Edge
+  # selenium-hub:
+  #   image: selenium/standalone-edge
+  #   depends_on:
+  #     - canvas-web
+  #   environment:
+  #     SE_NODE_GRID_URL: selenium-hub:4444/wd/hub
+  #   init: true
+  #   ports:
+  #     - "5902:5900"
+
+networks:
+  default:
+    external: true
+    name: "inst_shared"