Make LWEPlaintextLayout parameters public

[RasoulAM]

Make the parameters of LWEPlaintextLayout public so it can be initialized.

poulpy/poulpy-core/src/layouts/lwe_plaintext.rs

Lines 8 to 11 in 96d8f4c

	pub struct LWEPlaintextLayout {
	k: TorusPrecision,
	base2k: Base2K,
	}