fixes Bug 948533 (v74) - refactor CrashData and Priorityjobs middleware services

2nd PR to fix this problem

the CrashData service needs to invoke the Priorityjobs service if the requested processed crash is not processed yet.

The filesystem classes were hard coded to use the old Postgres Priorityjobs service while the hbase classes were hard coded to the correct RabbitMQ Priorityjobs service. The new 'hb' classes didn't even have a CrashData service.

This PR refactors the CrashData service for fs, filesystem, hb and hbase classes adding a Priorityjobs service "discovery". It then has the middleware default to using the modern hb and fs classes rather than the older filesystem and hbase classes

The config change that needs to be made:  eliminate all references in config to:
* socorro.external.hbase
* socorro.external.filesytem

in the middleware.ini [resources] section, change:
* [[hbase]] becomes [[hb]]
* [[filesystem]] becomes [[fs]]
* +include ./common_hbase.ini  becomes  +include ./common_hb.ini
* +include ./common_filesystem.ini  becomes  +include ./common_fs.ini