[solr] upgrade to solr 9

[pjfanning]

We have a compile issue with the Solr 9 libs. The getIdField method has been removed.

The Solr team suggested assuming the ID field is "id" because that is the norm anyway.

https://lists.apache.org/thread/fr3o9nntr0f4vj319rnm0zhxhqyyfyy2

We could maintain Solr 8 lib support by using reflection to see if the getIdField method is available and call it if found. If the method is not there, then just act as if the method was called and returned "id".