use nzshm-model to define OQ job runs

[chrisdicaprio]

rather than reading the same model definition using redundant code, use nzshm-model to read and parse the logic tree and create OQ jobs:

• hazard
• disaggregation
• runzi will no longer iterate though
  • logic trees
  • config ids
  • intensity_specs

PARKED
User defines if SRM logic tree for OQ to be run (slt_decomposition: ):

• full flattened logic tree: none
• one composite branch at a time: composite
• one component branch at a time: component

DONE WHEN:

• hazard uses nzhsm-model to build source_model.xml
• hazard does not iterate though the above args
• hazard can use any 3 of slt_decomposition options PARKED (#162)

Disagg split into new ticket.