Use admin account as payer on all outgoing transactions

[psiemens]

This issue was originally opened here by @tehranifar on July 28, 2021: onflow/wallet-api#12

We expect the admin account to contain enough FLOW to compensate for all custodial accounts' transactions.

Some endpoints (like FT withdrawal) use the user account as the payer, thus running into problems when transactions fail and the storage falls below the minimum.

All outgoing transactions from wallet-api should use the admin account as payer.

From @uhbif19:

@tehranifar

It looks to me that all transactions send by hand are paid by user. Flow are taken from account after each transaction. Am I correct?

From @tehranifar:

Yes, designating the admin account as payer will automatically make it pay for user transactions.

From @uhbif19:

I am not sure what you mean. 'designating the admin account as payer' - is that something possible in Wallet API? Or your answer is about situation when working with a regular Flow client libruary?

[latenssi]

Closing as duplicate of #139