By implementing a trivial strlcpy it's much easier to detect string
truncations and react to them. This also gives a noticeable speedup in
buffer handling (can be HUGE), since strlcpy() doesn't clear all the
buffer entry before writing data.

Converted all uses of strncpy() into strlcpy().

Also, we don't need to check for some null pointers, as there are no
malloc-like operations in the doAction loop.

Tell which statement is failing, which element in the batch, and give
its details.

Improve traceability while testing.

Stop considering it as an error, and make it display the information
from the Oracle server.

call tryResume(), so we have to return RS_RET_SUSPENDED. Otherwise, we
may keep losing messages until rsyslog is restarted.

If the database rejected some entry, making the statement fail on it,
the batch was not cleaned and the same values were retried over and
over, causing a cascade of failures and a denial of service.

We use now OCI_BATCH_ERRORS so that everything valid in the batch is
inserted, and rejected values can be discarded.

Instead of reading a complete line, we'll use a template and delegate
in the core to read such template. Then, all omoracle has to do is to
find that template and use it as the prepared statement.

I'm not sure if this is the correct approach, though. It has to dig
too much into rsyslog's structures...

txt_statement is stored in a private area, so that we don't mess too
much with rsyslog's internals (I still don't feel comfortable with
this much digging into template structures).