add support translator for lib module ex: boss_form from ngaranko

make easier to translate string through cb_admin panel for modules from the lib folder in a given cb app.

ex: boss_form from ngarango.

-module(login_form, [InitialData, Errors, Trans]).
-compile(export_all).

translatable_strings() ->
    [
     "Email", 
     "type email", 
     "Password", 
     "type password",
     "Password is too short"
    ].

form_fields() ->
    [
     {email, [{type, char_field},
                 {label, Trans("Email")},
                 {required, true},
                 {html_options, [{class, "input-large col-xs-12"},
                                {placeholder, Trans("type email")}]}]}
     ,{password, [{type, char_field},
                 {widget, password_input},
                 {label, Trans("Password")},
                 {required, true},
                 {html_options, [{class, "input-large col-xs-12"},
                                {placeholder, Trans("type password")}]}]}
}}]}
    ].