Store triggers by `DbId` and `TriggerId` instead of name

[hiltontj]

Problem

The ProcessingEngineManagerImpl stores triggers maps that use String names for databases and triggers:

influxdb/influxdb3_processing_engine/src/lib.rs

Lines 55 to 63 in 1f9849b

	#[derive(Debug, Default)]
	struct PluginChannels {
	/// Map of database to wal trigger name to handler
	wal_triggers: HashMap<String, HashMap<String, mpsc::Sender<WalEvent>>>,
	/// Map of database to schedule trigger name to handler
	schedule_triggers: HashMap<String, HashMap<String, mpsc::Sender<ScheduleEvent>>>,
	/// Map of request path to the request trigger handler
	request_triggers: HashMap<String, mpsc::Sender<RequestEvent>>,
	}

Proposed solution

• Change to using the DbId and TriggerId that identify these resources in the catalog.
• Methods that start/stop triggers should use these IDs as arguments instead of the names.