React to NATS+EventMesh backend config modifications on Eventing CR

[mfaizanse]

Currently, when an Eventing CR spec is created then the NATS/EventMesh subscription-manager object is initialised and started with the configurations from the CR. But if someone later changes the configs in the CR then it will not update it in the subscription-manager object.

Tasks:

• Identify if CR spec changed or not.
  • Keep an in-memory hash to identify if spec has changed. The hash should only be based on NATS/EventMesh relevant fields in the spec e.g. backend, logging etc.
  • If the spec changed then change the eventing CR status to Processing.
• If changed restart/re-init the NATS/EventMesh subscription-manager object with the new configs.
  • Do not do cleanup when stopping the NATS/EventMesh subscription-manager.
• If changing some config for NATS/EventMesh causes the subscription manager to start (because on backend we cannot change that config), then discuss with team that should we make that field immutable?

Acceptance Criteria:

• Changing the Spec should update the relevant NATS/EventMesh eventing infra.
• Do the implementation in separate PRs for NATS and EventMesh.

[grischperl]

Open, until EventMesh PR is merged