Use timeField variable on CSV import

We want to skip duplicate lines on CSV import. For this we need to use
time field, that is not necessarily the first field of the input. This
patch uses the configured time field instead of first one.

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Grab also the last column in CSV when requested

Signed-off-by: Miika Turkia <miika.turkia@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Remove old message directing users to use "Import CSV files" menu option

As importing files is now done through "Import Log Files" menu option for all
file types, the message directing users to use the specific "Import CSV Log Files"
non-existent menu entry should not be presented any more.

Signed-off-by: Rodrigo Severo <rodrigo@fabricadeideias.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>