Add some target fields and move some things around (#3879)

In preparation for putting proxy code in the api package this creates some necessary fields in the target output and it pre-moves credential parsing and proxy handshake code to their new places. This will make the diff for the actual proxy code move quite a bit smaller.

Co-authored-by: Johan Brandhorst-Satzkorn <johan.brandhorst@gmail.com>

internal/proto/controller/api/resources/targets/v1/target.proto

@@ -295,7 +295,8 @@ message WorkerInfo {
   string address = 10; // @gotags: `class:"public"`
 }
 
-// SessionAuthorizationData contains the fields needed by the proxy command to connect to a worker. It is marshaled inside the SessionAuthorization message.
+// SessionAuthorizationData contains the fields needed by the proxy command to
+// connect to a worker. It is marshaled inside the SessionAuthorization message.
 message SessionAuthorizationData {
   // Output only. The ID of the session.
   string session_id = 10 [json_name = "session_id"]; // @gotags: `class:"public" eventstream:"observation"`
@@ -315,6 +316,13 @@ message SessionAuthorizationData {
   // Output only. The connection limit being applied to this session. -1 means unlimited. This is not actually enforced on the client side but it provides for better listener handling by including it.
   int32 connection_limit = 90 [json_name = "connection_limit"];
 
+  // Output only. The endpoint port that will be connected to, either from a
+  // port directly on the target or from a service definition.
+  uint32 endpoint_port = 102 [json_name = "endpoint_port"]; // @gotags: `class:"public" eventstream:"observation"`
+
+  // Output only. The expiration time of the session.
+  google.protobuf.Timestamp expiration = 105; // @gotags: `class:"public" eventstream:"observation"`
+
   // Output only. The certificate to use when connecting. Raw DER bytes.
   bytes certificate = 120; // @gotags: `class:"sensitive"`
 
@@ -366,6 +374,13 @@ message SessionAuthorization {
   // Output only. The endpoint address that the worker will connect to, useful for setting TLS parameters.
   string endpoint = 100; // @gotags: `class:"public"`
 
+  // Output only. The endpoint port that will be connected to, either from a
+  // port directly on the target or from a service definition.
+  uint32 endpoint_port = 102 [json_name = "endpoint_port"]; // @gotags: `class:"public" eventstream:"observation"`
+
+  // Output only. The expiration time of the session.
+  google.protobuf.Timestamp expiration = 105; // @gotags: `class:"public" eventstream:"observation"`
+
   // Output only. The credentials for this session.
   repeated SessionCredential credentials = 110 [json_name = "credentials"];
 }