Consolidate Shading Relocation Patterns

[tjcelaya]

The idea of "normalizing" shading relocations was brought up by @cburroughs during review of #326. We should consider moving shaded classes to a unified root package to the resulting JAR is easier to work with. This would be a breaking change since it's possible for a user's IDE to autocomplete a class that is shaded, e.g. com.joyent.manta.org.apache.commons.io.IOUtils.

Current relocations:

com.joyent.http       -> com.joyent.manta.http
com.google            -> com.joyent.manta.com.google
org.apache            -> com.joyent.manta.org.apache
com.fasterxml         -> com.joyent.manta.com.fasterxml
io.mikael.urlbuilder  -> com.joyent.manta.io.mikael.urlbuilder
org.objenesis         -> com.joyent.manta.org.objenesis
com.rits              -> com.joyent.manta.com.rits

Proposed relocations:

com.joyent.http       -> com.joyent.manta.shaded.com.joyent.http
com.google            -> com.joyent.manta.shaded.com.google
org.apache            -> com.joyent.manta.shaded.org.apache
com.fasterxml         -> com.joyent.manta.shaded.com.fasterxml
io.mikael.urlbuilder  -> com.joyent.manta.shaded.io.mikael.urlbuilder
org.objenesis         -> com.joyent.manta.shaded.org.objenesis
com.rits              -> com.joyent.manta.shaded.com.rits