[LU-6429] add ability to use an external journals for all targets.

• Type: Improvement
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.8.0, Lustre 2.9.0
• Affects Version/s: Lustre 2.7.0
• Labels: patch
• Environment: any
• Assignee: WC Triage
• Reporter: Alexey Lyashkov

Description

test framework don't able to use an external journals for OST, MGS but it's usefull to simulate an customer configuration. External journal also don't work for DNE, as it's just single device per config.