Add possibility to auto-select account from wallet in auctionbid and loanpayback

[Jouzo]

What would you like to be added:

Currently, an address as to be passed in to bid on an auction or payback a loan.
This would improve the consistency between different RPCs.
Other RPC calls, such as addpoolliquidity and sendtokenstoaddress give the possibility to pass "*" or "{}" to auto-select an account from wallet.

It would also improve the UX.
Right now, a user has to calculate the right amount of token and send it to an address in order to be able to bid on an auction or payback a loan.

Why is this needed:

Consistency between RPCs
Better UX

[defichain-bot]

@Jouzo: Thanks for opening an issue, it is currently awaiting triage.

The triage/accepted label can be added by foundation members by writing /triage accepted in a comment.

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