MM-52981, MM-53559: Streamlined in-product marketplace (#24311)

server/Makefile

@@ -157,7 +157,8 @@ MMCTL_PACKAGES=$(shell $(GO) list ./... | grep -E 'server/v8/cmd/mmctl')
 TEMPLATES_DIR=templates
 
 # Plugins Packages
-PLUGIN_PACKAGES ?= mattermost-plugin-antivirus-v1.0.0
+PLUGIN_PACKAGES ?= $(PLUGIN_PACKAGES:)
+PLUGIN_PACKAGES += mattermost-plugin-antivirus-v1.0.0
 PLUGIN_PACKAGES += mattermost-plugin-autolink-v1.4.0
 PLUGIN_PACKAGES += mattermost-plugin-aws-SNS-v1.2.0
 PLUGIN_PACKAGES += mattermost-plugin-calls-v0.18.0
@@ -300,7 +301,7 @@ plugin-checker:
 	$(GO) run $(GOFLAGS) ./public/plugin/checker
 
 prepackaged-plugins: ## Populate the prepackaged-plugins directory
-	@echo Downloading prepackaged plugins
+	@echo Downloading prepackaged plugins: $(PLUGIN_PACKAGES)
 	mkdir -p prepackaged_plugins
 	@cd prepackaged_plugins && for plugin_package in $(PLUGIN_PACKAGES) ; do \
 		curl -f -O -L https://plugins-store.test.mattermost.com/release/$$plugin_package.tar.gz; \