add_resource_allocation_statics.sql

- Add DRAGNET max fill percentage to statics
- Add DRAGNET cluster resource description to python create virt instrument sql script
- Rework: create virt instrument sql script:
-- Remove TODOs and magic values, replaced by real resource capacities + comments how derived
-- All IDs are defined once and then referred by name
-- Add a few checks
-- Add NOTE that already assigned IDs can not be reused / shifted as long as used in operations
- Add new version of generated virt instrument sql script

Potential caveats:
- a few resource names have been renamed from 'bandwidth' and 'storage' to something less generic
- resource_group_to_resource_group: parent_id of LOFAR (root) is itself (0) instead of NULL
- resource_group_to_resource_group: some entries have been reordered (for sure not an issue)