Demote --scylla-data-dir and --scylla-yaml-file to schema source
helpers, rather than schema source in themselves. This practically means
that when these options are used, they won't define where the tool will
attempt to load the schema from, they will just be helpers to help locate
the schema, for whichever schema source the tool was instructed to use
(or left to choose).
--scylla-data-dir and --scylla-yaml-file being schema sources were
problematic with encryption at rest and for S3 support (not yet
implemented). With encryption, the tool needs access to the
configuration, so --scylla-yaml-file is often used to provide the path
to the configuration file, which contains encryption configuration,
needed for the tool to decrypt the sstable. Currently, using this option
implies forcing the tool to read the schema from the schema tables,
which is a problematic option for tests -- Scylla might be compacting a
schema sstable and this will make the tool fail to load the schema.
Demoting these options the schema helpers, allows providing them, while
at the same time having the option to use a different schema-source.
To allow the user to force the tool to load the schema from the schema
tables, a new --schema-tables option is added. Similarly, a
--sstable-schema option is introduced to force the tool to load the
schema from the sstable itself.
With this, each 4 schema source now has an option to force the use of
said schema source. There are various helper options to be used along
with these.
The documentation as well as the tests are updated with the changes.
The schema related documentation gets an rather extensive facelift
because it was a bit out-of-date and incomplete.
Fixes: scylladb/scylladb#20534Closesscylladb/scylladb#21678
ff90a77f5b