build: add Makefile with commands for common tasks

Makefile

@@ -0,0 +1,45 @@
+NAME          := grafana-prometheus-alertmanager-datasource
+VERSION       := $(shell git describe --always)
+
+## install: Install node dependencies
+.PHONY: install
+install:
+	yarn install
+
+## build: Build plugin
+.PHONY: build
+build:
+	yarn run build
+
+## sign: Sign plugin
+.PHONY: sign
+sign:
+	yarn sign
+
+## release: Make a release of the plugin
+.PHONY: release
+release: install build sign
+	mkdir build
+	mv dist/ build-camptocamp-prometheus-alertmanager-datasource
+	zip -r build/camptocamp-prometheus-alertmanager-datasource-${VERSION}.zip ./build-camptocamp-prometheus-alertmanager-datasource
+	md5sum build/camptocamp-prometheus-alertmanager-datasource-${VERSION}.zip > build/camptocamp-prometheus-alertmanager-datasource-${VERSION}.zip.md5
+	rm -r build-camptocamp-prometheus-alertmanager-datasource
+
+## run-dev: Build and run Docker dev container on port 3000
+.PHONY: run-dev
+run-dev: build
+	docker run -d \
+    -e GF_DEFAULT_APP_MODE=development \
+    -p 3000:3000 \
+    -v ${PWD}:/var/lib/grafana/plugins \
+    grafana/grafana:8.5.2
+
+
+.PHONY: help
+all: help
+help: Makefile
+	@echo
+	@echo " Choose a command to run in "$(NAME)":"
+	@echo
+	@sed -n 's/^##//p' $< | column -t -s ':' |  sed -e 's/^/ /'
+	@echo