Rename livekit_server to livekit_api (#24984)

The name `livekit_server` was a bit misleading as it is not a server and
gets built into both the client and server - the server code is in
`collab`.

Release Notes:

- N/A

crates/livekit_api/vendored/protocol/livekit_webhook.proto

@@ -0,0 +1,36 @@
+syntax = "proto3";
+
+package livekit;
+option go_package = "github.com/livekit/protocol/livekit";
+option csharp_namespace = "LiveKit.Proto";
+option ruby_package = "LiveKit::Proto";
+
+import "livekit_models.proto";
+import "livekit_egress.proto";
+import "livekit_ingress.proto";
+
+message WebhookEvent {
+  // one of room_started, room_finished, participant_joined, participant_left,
+  // track_published, track_unpublished, egress_started, egress_updated, egress_ended, ingress_started, ingress_ended
+  string event = 1;
+
+  Room room = 2;
+
+  // set when event is participant_* or track_*
+  ParticipantInfo participant = 3;
+
+  // set when event is egress_*
+  EgressInfo egress_info = 9;
+
+  // set when event is ingress_*
+  IngressInfo ingress_info = 10;
+
+  // set when event is track_*
+  TrackInfo track = 8;
+
+  // unique event uuid
+  string id = 6;
+
+  // timestamp in seconds
+  int64 created_at = 7;
+}