Investigate approach for reusable test resources

Test resources are currently in place for individual tests across ERM components. This risks resources not being updated across tests when localized changes are made, which can lead to regressions not being identified. 

Centralising test resources will reduce duplication, maintenance and improve consistency. 

This spike will:

1. examine constraints, patterns or opportunities for structuring centralised reusable test resources across ERM components
2. examine opportunities or constraints to be aware of for reusing centralised test resources for end-to-end tests going forward (to avoid future duplication) 
3. document the approach to be taken and rationale for incrementally transitioning to reusable test resources as part of
   1. current RTL migration effort
   2. business-as-usual test updates where migration to RTL has already occurred
4. document any changes needed to be made for future test migration / re-work, including relevant examples. 
5. define any necessary characteristics to ensure resources are consistently set up and support expected test scenarios
6. identify fundamental test resource types and scenarios to prioritise, if appropriate (eg, refdata, shared components)

Timebox: 3d