There is a difference how ScyllaDB and Cassandra handle conditional
batches with different IF statements (such as "IF EXISTS" and "IF NOT
EXISTS").
This commit explicitly documents the differences in the behavior.
Refs: #13011
This commit moves the Features page from the section for developers
to the top level in the page tree. This involves:
- Moving the source files to the *features* folder from the *using-scylla* folder.
- Moving images into *features/images* folder.
- Updating references to the moved resources.
- Adding redirections to the moved pages.
Closesscylladb/scylladb#20401
