JVM assemblies: Pick a naming convention for shading and stick to it

[arielshaqed]

We currently have a variety of different formats for shaded names in our JVM assemblies. Additionally many of these names do not include any organizationally-unique prefix, meaning that they could collide with other shaded names in Spark assemblies from other organizations!

Select a single consistent prefix format that includes either "lakefs" or "treeverse" (suggestion: io.lakefs.<client>.shaded), and use that consistently.