Making sql_yacc.yy close to sql_yacc_ora.yy:

1. Adding struct sp_cursor_name_and_offset into %union
2. Adding field_type_numeric, field_type_string,  field_type_lob,
   field_type_temporal, field_type_misc
3. Adding keyword_sp_data_type and keyword_sp_not_data_type
4. Removing "opt_savepoint". Moving this grammar to "rollback" instead.
   This fixes one shift/reduce conflict.
5. Minor indentation cleanup.