At application start, the account tab does not display unclaimed UDs

unclaimed UDs not display at start of application.

accounts should store:

• balance: total balance with unclaimed UDs
• balance_available: only balance available (without unclaimed UDs)

GUI should display only total balance:

• When a transfer is done, it should be limited to the total balance amount in the spin box.
• When a transfer is done, if it exceeds the balance_available value, then a claim_uds is done, before doing the transfer.
• Then the balance_available is updated after the claim_uds is done.
• Remove the display of unclaimed UDs amount under account balance.