Improvements to autosync in bankstatments task#26199

Issue #20 (closed) is solved here

Before

• Auto sync just add the lines to a new bank statment

After

• Starting balance is set and extra line is removed.
• 
• If an previous statment exists it will take its end balance as its start (this statements were created synchronizing data demo)
• 
• In the journal form now you can choose the Creation of bank statement type (daily, weekly, per sycn, etc) the online sync will decide if create a new statement or add the lines to the current one depending of the configuration chosen.
• Here you can see an example