Add RestrictedTransfers proxy type

[hieronx]

centrifuge/apps#718

• The proxy is able to do any transfer
• The proxied account with the RestrictedTransfers type is limited to a set number of accounts which funds can be sent to
• The proxy can update this list of accounts

Should be able to define destinations per currency type.

Should also support limiting which destinations on other chains it can be transferred to using XCM and/or Connectors.

[mustermeiszer]

@offerijns didn't we already add the proxy type or is this a more complex version of

centrifuge-chain/runtime/development/src/lib.rs

Lines 389 to 414 in 4c5bb84

	ProxyType::Borrower => matches!(
	c,
	Call::Loans(pallet_loans::Call::create{..}) |
	Call::Loans(pallet_loans::Call::borrow{..}) |
	Call::Loans(pallet_loans::Call::repay{..}) |
	Call::Loans(pallet_loans::Call::write_off{..}) |
	Call::Loans(pallet_loans::Call::close{..}) |
	// Borrowers should be able to close and execute an epoch
	// in order to get liquidity from repayments in previous epochs.
	Call::Loans(pallet_loans::Call::update_nav{..}) |
	Call::Pools(pallet_pools::Call::close_epoch{..}) |
	Call::Pools(pallet_pools::Call::submit_solution{..}) |
	Call::Pools(pallet_pools::Call::execute_epoch{..})
	),
	ProxyType::Investor => matches!(
	c,
	Call::Pools(pallet_pools::Call::update_invest_order{..}) |
	Call::Pools(pallet_pools::Call::update_redeem_order{..}) |
	Call::Pools(pallet_pools::Call::collect{..}) |
	// Investors should be able to close and execute an epoch
	// in order to get their orders fulfilled.
	Call::Loans(pallet_loans::Call::update_nav{..}) |
	Call::Pools(pallet_pools::Call::close_epoch{..}) |
	Call::Pools(pallet_pools::Call::submit_solution{..}) |
	Call::Pools(pallet_pools::Call::execute_epoch{..})
	),

[hieronx]

@mustermeiszer What we already added was #734. This just limited the calls which these proxy types could make. This ticket is actually having the ability to limit destinations to which a proxied account can send currency to.

[mustermeiszer]

Ah, I see. Well, this will need a pallet then.

[branan]

Branan to write up their thoughts/proposal