fix: Add support for multi platform image builds in docker

[alecthegeek]

Makefile changes:

1. Add new variable for Docker user name, called DOCKER_USER, defaults to "jdkato"
2. Add new variable for list of platforms, called DOCKER_BUILD_TARGETS
3. Add new docker buildx commands to create and remove docker build containers
4. Modify docker buildx build command to support DOCKER_BUILD_TARGETS and DOCKER_USER
5. Change the way docker login is done (--password-stdin) to avoid annoying security warning
6. Change LAST_TAG, LDFLAGS, and CURR_SHA to simply expanded variables to improve performance

Dockerfile changes

1. Add new ARG value for Go version, called GOLANG_VER, defaults to "1.21"
2. Remove GOOS=$TARGETOS GOARCH=$TARGETARCH and related definitions
3. Remove "--platform=$BUILDPLATFORM" in FROM line

Assumptions:

Building and pushing Docker images is a manual process that takes place on the developer’s machine.

Integration into the GitHub actions would be desirable, but will require additional work.

Testing Notes:

Tested in a Git checkout with the command

make DOCKER_USER=<Docker Hub Username> DOCKER_PASS='<Docker Hub Token>' docker
docker container run -it --rm <Docker Hub Username>/vale --version

Tested on macOS host. it was necessary to disable Rosettta support

Related to #859

[jdkato]

Thanks!

[alecthegeek]

You are very welcome.