hack, made maven version info available at expected location

many existing plugins use META-INF/maven/org.apache.maven/maven-core/pom.properties
to discover maven version of the runtime. longer term,
we need to better define what "maven runtime version means"
and how to plugins can find it. for now though, make expected
pom.properties file part of tesla maven-core jar. note that the file
uses ${project.version}, which assumes tesla and maven versions
are aligned.

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>