Support recording sampleRate

[id0Sch]

As a way to limit traffic and data usage, we (at the company I work for) implemented a recording sampleRate mechanism over the legacy snippet.

we do something like this:

const sampleRate = 0.02

.....

require('./external/fullstory') 
window.FS.shutdown() 

if (Math.random() <= sampleRate) {
	....
	window.FS.restart()
}

It could be nice to have this functionality come out of the box via the npm module.
Let me know what you think.
Thanks!

[patrick-fs]

Hey @id0Sch thanks for your suggestion! We'll look into this.