[server] Fix crypto deprecation warning.
On launching the server we have the following log warning :
(node:16192) [DEP0091] DeprecationWarning: crypto.DEFAULT_ENCODING is deprecated. [2]
(node:16192) [DEP0010] DeprecationWarning: crypto.createCredentials is deprecated. Use tls.createSecureContext instead. [2]
(node:16192) [DEP0011] DeprecationWarning: crypto.Credentials is deprecated. Use tls.SecureContext instead.
This MR corrects the error.