Update *alter_sessions action

Will now support two extra parameters: address and codec. For *internal
connections, the birpc.Service object will be retrieved from rpcParamsMap
from utils. Supported codecs: <*gob|*json|*http_jsonrpc> (ingored for
*internal address).

Action does not bother with setting defaults anymore, lets the API
handle them.

Improve action comments.

Add unit tests for the action. UnregisterRpcParams' implementation was
required.

Updated *alter_sessions action tariffplan for radius coa integration test
to include address and codec.

Some birpc clients that are set up in integration tests were still registering
a SessionSv1 object. Updated them to register an AgentV1 object instead.

utils/rpc_params.go

@@ -21,6 +21,7 @@ package utils
 import (
 	"fmt"
 	"reflect"
+	"strings"
 	"sync"
 
 	"github.com/cgrates/birpc"
@@ -86,3 +87,14 @@ func GetRpcParams(method string) (params *RpcParams, err error) {
 	}
 	return
 }
+
+func UnregisterRpcParams(name string) {
+	rpcParamsLock.Lock()
+	defer rpcParamsLock.Unlock()
+	for method := range rpcParamsMap {
+		if strings.HasPrefix(method, name) {
+			delete(rpcParamsMap, method)
+		}
+	}
+	delete(rpcParamsMap, name)
+}