build: move to multistage docker

[musicEnfanthen]

This PR rewrites the dockerfile to use a multistage docker build. This builds git, node, ant and prince in parallel and reduces the build size.

Needs to be tested on arm64.

[bwbohl]

just a short question: what do we actually need git for?

[musicEnfanthen]

just a short question: what do we actually need git for?

    <target name="get-local-git-sha" description="Retrieves the local git sha.">
        <exec executable="git" outputproperty="github.sha.local">
            <arg value="describe"/>
            <arg value="--match=NeVeRmAtCh"/>
            <arg value="--always"/>
            <arg value="--abbrev"/>
            <arg value="--dirty"/>
        </exec>
        <echo>Local github.sha: ${github.sha.local}</echo>
    </target>

    <target name="get-local-git-branch" description="Retrieves the current git branch via command line.">
        <exec executable="git" outputproperty="github.branch.local">
            <arg value="branch"/>
            <arg value="--show-current"/>
        </exec>
        <echo>Local github.branch: ${github.branch.local}</echo>
    </target>

These targets will fail if git executable is not available.

[rettinghaus]

Building locally on my M3 Mac works fine, just the payload is smaller