Adds basic configuration option for logs.

The integration tests are failing now,
because log collection is not implemented yet.
Implementing it is the next step.
The initial implementation in the next step should be the most naive possible:
just running the provided query every collection interval,
without any tracking of the data that has already been read.

Perhaps the log collection integration tests
should be separated from the metrics collection
integration tests for greater visibility
into what is working and what is failing.

The panic is useful for testing.
When this feature is complete,
the panics must be replaced with error logging.

At this stage, the logs query is run only once
per collector run, e.g. collection_interval is ignored.
Reflect this in the tests before implementing
collecting logs on interval.

Oracle expects uppercase column names.

Collecting logs every collection interval.
To prevent collecting duplicates,
we need to track the already collected logs,
which is going to be the next step.

This initial implementation supports only integer tracking columns.
The next type to support should be datetime/timestamp.
We should also support using persistent storage for the tracking value.

…estamp-for-tracking-column

SQL Query receiver - support timestamp in tracking column

…dd-logs

…tion-tests

fix integration tests

…-mysql-integration-test

SQL Query receiver: add logs to mysql integration test

This prevents a "busy port" error when running
one of the tests repeatedly.

feat: persist tracking value in storage

The `$` character needs to be escaped with `$$` in Otelcol config files.

feat(sqlqueryreceiver) add traces to monitor logs received

After introducing integration test framework

When the component needs to be shut down before it was properly started
(for example due to a configuration erro
like using a storage extension that does not exist),
we need to check if variables have been initialized
to prevent panics due to nil pointer dereference.