add indices for resc_id and data_is_dirty

[trel]

• master
• 4-2-stable

---

1. implement new index for both resc_id and data_is_dirty on r_resc_main table
2. investigate and post speed improvements for moderate-sized table (1M rows?)

Discovered when looking for out-of-date replicas and matching by resource hierarchy (now that resc_name is no longer used).

[trel]

• sample database - r_data_main has 309M rows
• sample query filtering on resc_id takes 116 seconds
• added index with create index idx_data_main7 on R_DATA_MAIN (resc_id);
• index took 300 sec to create
• same query ran in 16 seconds (>7x faster)