admin-ui docker image does not start because of configuration file overwrite

[bnouwt]

Version 1.3.1 of the admin-ui docker image does not work (it crashes with an error about missing configuration). This is caused by the maven-shade-plugin which merges multiple jars together and (by default) overwrites files, while in the case of microprofile-config.properties we would like to merge them. This is possible, by adding the following to the pom.xml maven-shade-plugin section:

	<transformer
		implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
		<resource>
			META-INF/microprofile-config.properties</resource>
	</transformer>