Present only right accounts during import of statements

During import of investment statement user is asked to select account
into which he wants to import. He should choose investment account, but
he is also presented with all other sorts of accounts. This patch makes
sure that user is presented only with the right account types.

FEATURE: 363069
REVIEW: 127915

Signed-off-by: Łukasz Wojniłowicz <lukasz.wojnilowicz@gmail.com>