Change types and interfaces for AccountUpgradeRequest

[brh28]

• Creates GQL Inputs for Address and Bank Account, which map to ErpNext DocTypes
• Splits BusinessUpgradeRequestInput into a ProUpgradeRequest & MerchantUpgradeRequest
• Simplifies Validation logic using existing validator
• Removes automatic upgrades for Pro
• set terminalsRequested as an int (validation asserts max of 1)
• updates return values with the request id so that it can be later queried/handled

[brh28]

Note, Account Upgrade Request Doctype needs to be update in flash-frappe-admin. This PR has been successfully tested and creates the following sample:

[islandbitcoin]

looks like this needs a rebase

[islandbitcoin]

LGTM

[islandbitcoin]

LGTM