Improve locale_strings map by re json.encode.
Add method to put translation jsons into txn var and read with a json_query fetch inside template files not served by a lua view e.g. maintenance page
Fixes potential issue of challenges being incorrect if solved right on the bucket change
Allows to solve a challenge at any time (even in the background) and not see the challenge page twice in a small period
Allows for backend to make dynamic expiry of tokens e.g make tor tokens or based on IP reputation not last as long (not implemented atm)
Close#20
