Idea by kerio: clearbufferonmsg setting

[jpnurmi]

The current behavior mimics AutoClearXxxBuffer. Add a settings to make it behave like clearbufferonmsg.

[RX14]

👍 I didn't realise this module didn't have this functionality

[michalrus]

Also, as we know which identity saw what, the buffers might be partially cleared accordingly.