pythonPackages.pythondaemon: rename to pythonPackages.python-daemon

This commit renames the pythondaemon module to match its module name, github
name, and pypi name, which makes it easier to find and reference. In order to
avoid breaking any external users, I've left an alias with a deprecated warning.

pkgs/development/python-modules/libagent/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchPypi, buildPythonPackage, ed25519, ecdsa , semver, mnemonic,
   unidecode, mock, pytest , backports-shutil-which, ConfigArgParse,
-  pythondaemon, pymsgbox }:
+  python-daemon, pymsgbox }:
 
 buildPythonPackage rec {
   pname = "libagent";
@@ -12,7 +12,7 @@ buildPythonPackage rec {
   };
 
   propagatedBuildInputs = [ unidecode backports-shutil-which ConfigArgParse
-    pythondaemon pymsgbox ecdsa ed25519 mnemonic semver ];
+    python-daemon pymsgbox ecdsa ed25519 mnemonic semver ];
 
   checkInputs = [ mock pytest ];