Document better all available attributes for filtering

[grcevski]

There are couple of issues in our attribute selection docs:

1. Some of the attribute series names are outdated, like sql, redis, which is now called db.operation.duration.seconds.
2. Some of our examples also refer to the old names, e.g. sql
3. We don't list anywhere what are the available attributes for each collection. We should list them or point to the OTel docs for each section.