apollo_dashboard,apollo_deployments: add top-level intervalSec to Alerts; use it in alert builder

Move the evaluation interval from a per-alert field to a top-level field
on the Alerts struct. The interval is group-scoped in Grafana, so a single
value for all alerts is the correct model.

Also restructure alert_builder.py to upload/dump per rule-group instead of
per individual alert, using the top-level intervalSec as the group interval.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Itay-Tsabary-Starkware

Cargo.lock

@@ -42,6 +42,7 @@ apollo_transaction_converter.workspace = true
 blockifier.workspace = true
 indexmap = { workspace = true, features = ["serde"] }
 serde = { workspace = true, features = ["derive"] }
+strum = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true, features = ["arbitrary_precision"] }
 serde_with.workspace = true