FINERACT-2633: Rework datasource connection handling

[adamsaghy]

Description

Connection pool exhaustion issues were noticed.

Following optimizations were done:

• Close more aggressively datasource connections (where applicable)
• Reworked COB locking to rely on JDBC Repositories solely (no mixed JPA + JDBC connections around locking)
• Separate 3 kind of transaction managers:
  • JPA transaction manager (default)
  • JDBC transaction manager (used by new command framework)
  • Batch job JDBC transaction manager (used by Spring Batch for JDBC repository operations)
• Connection pool exhaustion diagnostics added

Checklist

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[budaidev]

LGTM

[Cocoa-Puffs]

LGTM!