CSPACE-3053: Updated read me file with a first pass at designating 'largetext' fields...

CSPACE-3053: Updated read me file with a first pass at designating 'largetext' fields in object and procedural records - those which require storage of > 500 characters, which is Nuxeo's per-field default for MySQL.  The contents of this file must currently be pasted into an active Nuxeo default-repository-config.xml configuration file, such as in /usr/local/share/jboss/templates/collectionspace_mysql/config, and per a follow-on JIRA, might instead be integrated int the services deployment process.