* VAULT-22481: Audit filter node (#24465)
* Initial commit on adding filter nodes for audit
* tests for audit filter
* test: longer filter - more conditions
* copywrite headers
* Check interface for the right type
* Add audit filtering feature (#24554)
* Support filter nodes in backend factories and add some tests
* More tests and cleanup
* Attempt to move control of registration for nodes and pipelines to the audit broker (#24505)
* invert control of the pipelines/nodes to the audit broker vs. within each backend
* update noop audit test code to implement the pipeliner interface
* noop mount path has trailing slash
* attempting to make NoopAudit more friendly
* NoopAudit uses known salt
* Refactor audit.ProcessManual to support filter nodes
* HasFiltering
* rename the pipeliner
* use exported AuditEvent in Filter
* Add tests for registering and deregistering backends on the audit broker
* Add missing licence header to one file, fix a typo in two tests
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Co-authored-by: Peter Wilson <peter.wilson@hashicorp.com>
* Add changelog file
* update bexpr datum to use a strong type
* go docs updates
* test path
* PR review comments
* handle scenarios/outcomes from broker.send
* don't need to re-check the complete sinks
* add extra check to deregister to ensure that re-registering non-filtered device sets sink threshold
* Ensure that the multierror is appended before attempting to return it
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Co-authored-by: Peter Wilson <peter.wilson@hashicorp.com>
