[REF] account_bank_statement_import: moved the content of account_additions.py in account_bank_statement_import.py
[IMP] base, currency: improved error message given when no rate is associated to the given date
[IMP] account: added new fields accounts_code_digits and bank_account_code_char in view + added default value to allow the import of file in demo instances
[FIX] account: typo in field names
[IMP] base, currency: set the date of currency rates as of the 1st of January 2010 so that we have a broader range for tests and we can import sample files for bank statements in multi-currencies that aren't in the current year. Moreover creating rates from the 1st of the current year was as much arbitrary and without any added value
[FIX] account_bank_statement_import_qif: as the .QIF format does not allow to detect the journal automatically, we need to let the user choose it in the wizard