pass-secret-service: various improvements

Allow setting the application package and storePath used by the
config. Since the `programs.password-store` Home Manager module sets
config values via global environment variables, the default behavior
of the module should continue to behave as before for the user.

Additionally,

- Adds a few tests.

- Use "escapeShellArg" function call to the path parameter call to
  ensure paths with spaces work.

- Allow not setting storePath, which will cause `pass_secret_service`
  to default to using `~/.password-store`.

- If `pass-secret-service` is enabled, set its store path to default
  to the one defined in our password-store environment settings.

- Add myself (houstdav000) as maintainer.

modules/programs/password-store.nix

@@ -59,6 +59,9 @@ in {
     home.packages = [ cfg.package ];
     home.sessionVariables = cfg.settings;
 
+    services.pass-secret-service.storePath =
+      mkDefault cfg.settings.PASSWORD_STORE_DIR;
+
     xsession.importedVariables = mkIf config.xsession.enable
       (mapAttrsToList (name: value: name) cfg.settings);
   };