i18n cleanup

* "zero-config-whitelisted_langs-all" - move to ZeroPortal as "zeroportal-all-langs"

* "zero-config-errors_found" - obsolete, remove

* "zero-config-json" - move to JsonConfig as "jsonconfig-bad-json"
* "zero-config-optional-field" - move to JsonConfig as "jsonconfig-optional-field"
* "zero-config-duplicate_field" - move to JsonConfig as "jsonconfig-duplicate-field"
* "zero-config-opt_bool" - move to JsonConfig as "jsonconfig-err-bool"
* "zero-config-opt_string" - move to JsonConfig as "jsonconfig-err-string"

Change-Id: I142733c4112584d4a90dc8f925682cc03fd4e3e9