update config name -> core/apiName

C. Fahner <info@fahnerit.com>
add DocumentStore, initial commit

C. Fahner <info@fahnerit.com>
remove DocumentStore::listAll, has no use for now

C. Fahner <info@fahnerit.com>
update DocumentStore to work with snapshots instead of whole documents

C. Fahner <info@fahnerit.com>
rename KeyValueStore collection to 'keyvals'

C. Fahner <info@fahnerit.com>