osmosis-price-oracle: Add discount factor

[maurolacy]

The simple price feed contract has a discount factor, so that cross-staking can be made a little less profitable than native staking.

Let's introduce this discount factor to the osmosis price feed contract as well.

[maurolacy]

Correction: This is already being implemented at the converter level

mesh-security/contracts/consumer/converter/src/contract.rs

Lines 43 to 59 in 191ae6f

	/// We must first instantiate the price feed contract, then the converter contract.
	/// The converter will then instantiate a virtual staking contract to work with it,
	/// as they both need references to each other. The admin of the virtual staking
	/// contract is taken as an explicit argument.
	///
	/// Discount is applied to foreign tokens after adjusting foreign/native price,
	/// such that 0.3 discount means foreign assets have 70% of their value
	#[msg(instantiate)]
	pub fn instantiate(
	&self,
	ctx: InstantiateCtx,
	price_feed: String,
	discount: Decimal,
	remote_denom: String,
	virtual_staking_code_id: u64,
	admin: Option<String>,
	) -> Result<Response, ContractError> {

Closing.