Add look up messages map

[knatnaela]

No description provided.

[andresaraujo]

@knatnaela

Sorry I don't want to add all the locales in the map by default, the reason is that it will will increase the size of all the apps that load this library because they will include all these locales even if they don't use it. ( maps cannot be tree-shaken by the Dart compiler)

I might event remove spanish in the default map in the next major version, so users only load the locales they need.

EDIT:
Btw am messages are already included ready to import

[knatnaela]

ohh I see okay thanks.