Ability to seed the random generator

[kernel-panic96]

If someone uses this in tests, the inability to seed the random number generator will cause unreproducible test flakiness.

[davidporos92]

I think it is possible by calling the following function with a seeded rand:

go-randomdata/random_data.go

Lines 102 to 104 in 26f4a64

	func CustomRand(randToUse *rand.Rand) {
	privateRand.pr = randToUse
	}

[Pallinder]

Closing this one (see above)