Add RUM Sample Rate Audit

[solaris007]

There have been cases where the RUM sample rate was set to e.g. 1 instead of the recommended 100. Context: https://adobe-dx-support.slack.com/archives/C050M6XFWCF/p1713347373771179

@trieloff @kptdobe anything to add as to the value of this audit?

[trieloff]

I'd check for domains where the average sampling rate is too low (<10)