1. remove the option to disable AOF preamble RDB this adds a lot of code to redis and modules
2. delete all the code in rewriteAppendOnlyFileRio and deprecate modules aof_rewrite callback
3. always generate base rdb (even when starting empty) (done in Always create base AOF file when redis start from empty. #10102)
4. disallow BGREWRITEAOF command when appendonly is off?

details: #9539 (comment)