Indexing STOP Command

User Story

As an administrator, I want to be able to abort indexing at any point, so that I can prevent large numbers of simultaneous processes from overwhelming the system, and preventing search operations.

Acceptance Criteria (Must Have)

1. It must be possible for an administrator to abort indexing (including any required as a result of the FIX tool) mid-way through processing.
2. It must be possible to pick-up indexing again, and resume normal business operations following an abort. I.e. you shouldn't have to re-index anything that was indexed successfully before the abort, and there shouldn't be any gaps in what gets indexed.

Acceptance Criteria (Could Have)

1. It must be possible for an administrator to specify whether an abort will stop all indexing, only indexing resulting from a FIX command, or only indexing not resulting from a FIX command.

Implementation Notes

Suggested implementation is via an additional STOP command, with parameters as needed.