CORE: proper way of selecting RichResource

 - created inner RichResourceExtractor class which can select
 rich resource with all resource tags assigned by one SQL query
 - used when selecting RichResources
 - usage of JdbcTemplate instead of SimpleJdbcTemplate in order to
 use RichResourceExtractor class instead of RowMapper
 also: SimpleJdbcTemplate is deprecated in Spring now
 - added method to fill tags in RichResource one by one (used
 by RichResourceExtractor)
 - updated toString() a serializeToString() in RichResource