bbb-lti v0.1: Default welcome message is localized to English, Spanish and French

...s/org/bigbluebutton/web/controllers/ToolController.groovy

bbb-lti/grails-app/i18n/messages.properties

bbb-lti/grails-app/i18n/messages_de.properties

bbb-lti/grails-app/i18n/messages_es.properties

bbb-lti/grails-app/i18n/messages_fr.properties

bbb-lti/grails-app/i18n/messages_it.properties

bbb-lti/grails-app/i18n/messages_ja.properties

bbb-lti/grails-app/i18n/messages_nl.properties

bbb-lti/grails-app/i18n/messages_pt_BR.properties

bbb-lti/grails-app/i18n/messages_ru.properties

bbb-lti/grails-app/i18n/messages_th.properties

bbb-lti/grails-app/i18n/messages_zh_CN.properties