Complete rewrite for modern Solr installation

[geerlingguy]

Solr has improved quite a bit since the initial version of this role was written (for early 3.x versions of Solr). In Solr 4.x and now 5.0.0 (just released), it's preferred to use the included Jetty-based servlet, which is simpler to install and configure than Tomcat.

Plus, I only have a crufty old 'tomcat6' role to use, and don't have any other projects where I use Tomcat anymore, so there's no real reason for me to create or update tomcat roles. And since Jetty's preferred anyways, and should have comparable performance nowadays... no reason not to use Jetty :)

So I'm going to completely rewrite the role, and still hopefully be able to support any version of Solr from 3.x to 5.x, installed with Java 7+. I can also drop the dependency on geerlingguy.tomcat6, and just have no dependencies (people can install Java however they please... though the geerlingguy.java role makes this simple as well).

[geerlingguy]

It looks like things may be changing a little bit with 5.x, too... but for reference:

• https://cwiki.apache.org/confluence/display/solr/Taking+Solr+to+Production
• https://cwiki.apache.org/confluence/display/solr/Running+Solr

[geerlingguy]

It looks like Solr 5.x will definitely require a bit of a rework, since file paths have moved around a bit, and setup/configuration is a bit different (see the init script in the first link in the above comment).

But for 3.x and 4.x, file pathing is similar.

[geerlingguy]

Also need to account for settings like Xmx and Xms with this rewrite... any other Jetty vars?