MM-51792 Replace Boards feature flag with env var (#22739)

* remove Boards feature flag from server, makefile, and docker

* Update server/boards/server/boards_service_util.go

Co-authored-by: Miguel de la Cruz <miguel@mcrx.me>

---------

Co-authored-by: Miguel de la Cruz <miguel@mcrx.me>

server/docker-compose.yaml

@@ -109,7 +109,6 @@ services:
       - "RUN_SERVER_IN_BACKGROUND=false"
       - "MM_CLUSTERSETTINGS_ENABLE=true"
       - "MM_CLUSTERSETTINGS_CLUSTERNAME=mm_dev_cluster"
-      - "MM_FEATUREFLAGS_BoardsProduct=true"
     networks:
       - mm-test
     depends_on:
@@ -147,7 +146,6 @@ services:
       - "RUN_SERVER_IN_BACKGROUND=false"
       - "MM_CLUSTERSETTINGS_ENABLE=true"
       - "MM_CLUSTERSETTINGS_CLUSTERNAME=mm_dev_cluster"
-      - "MM_FEATUREFLAGS_BoardsProduct=true"
     networks:
       - mm-test
     depends_on:
@@ -185,7 +183,6 @@ services:
       - "RUN_SERVER_IN_BACKGROUND=false"
       - "MM_CLUSTERSETTINGS_ENABLE=true"
       - "MM_CLUSTERSETTINGS_CLUSTERNAME=mm_dev_cluster"
-      - "MM_FEATUREFLAGS_BoardsProduct=true"
     networks:
       - mm-test
     depends_on: