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).

This directive controls the amount of memory needed for properties in
the batch. Users should specify the largest value they expect in the
statement. As per Rainer's comment:

on MAX_BUFSIZE: I'd tend to make this configurable, because with
RFC5424 messages can be much longer and RFC5425 now recommends a
minimum maximum size of 8K.

So we let users to choose. Maybe we need a sensible default value to
make users' lifes easier?

Also, the old non-vector based interface is not supported anymore. I
broke it already when moving to this stage.