Dockerfile: conditionally change coin name in gettext via env

docker/Dockerfile

@@ -19,6 +19,9 @@ RUN mix do deps.get, deps.compile
 
 ADD . .
 
+ARG COIN
+RUN if [ "$COIN" != "" ]; then sed -i s/"POA"/"${COIN}"/g apps/block_scout_web/priv/gettext/en/LC_MESSAGES/default.po; fi
+
 # Run forderground build and phoenix digest
 RUN mix compile
 

docker/Makefile

@@ -53,7 +53,7 @@ ifdef HAS_BLOCKSCOUT_IMAGE
 	@echo "==> Image exist. Using $(DOCKER_IMAGE)"
 else
 	@echo "==> No image found trying to build one..."
-	@docker build -f ./Dockerfile -t $(DOCKER_IMAGE) ../
+	@docker build --build-arg COIN="$(COIN)" -f ./Dockerfile -t $(DOCKER_IMAGE) ../
 endif
 
 migrate: build postgres