* add tag handler for snowflake ids
* add snowflake generator
* fill snowflake id back to the bean
* table driven test, mockable snowflake generator
* use math/rand/v2
* snowflake without time.sleep
* more explicit bitwise modulo
* rename snowflake to randomid
* remove unused part of xorm
* remove onlytodb and onlyfromdb tags
* only keep snapemapper, since we always assumed it is the only one available in xorm