[Improvement] Importing of transaction files

[rafacla]

Things to improve:

• [x] May import OFX and XLS (PDF?)
• [ ] Option to identify when a file doesn't have headers
• [ ] Option to pick the columns for each kind of column (not need to edit the file to include/change the header names)
• [ ] Option/auto identify number format (decimal separator) and also the column separador (comma, semmi comma, etc)...
• [x] Option to auto classify the transactions (Rules view)
• [x] Identify repeated transactions and to merge new information?

[rafacla]

• [x] currently, it looks for the names in small caps, ignore caps is a must
• [ ] importing transactions may breake upon number formatting (for example, it may correctly identify in the format 0.00, but breaks in 0,000.00 (thousands) when it identifies the decimal separator as "," and not ".", maybe related to the default locale being set as pt-br
• [ ] credit card transactions has swapped values (negative and positive), may be a good idea to warn the user if it looks strange when importing.
• [x] importing files should redirect for the original url with filters