CDC log uses `bytes` to deal with cells and their values, and linearizes all
values indiscriminately. This series makes a switch from `bytes` to
`managed_bytes` to avoid that linearization.
Fixes#7506.
Closes#8429
* github.com:scylladb/scylla:
cdc: log: change yet another occurence of `bytes` to `managed_bytes`
cdc: log: switch the remaining usages of `bytes` to `managed_bytes` in collection_visitor
cdc: log: change `deleted_elements` in log_mutation_builder from bytes to managed_bytes
cdc: log: rewrite collection merge to use managed_bytes instead of bytes
cdc: log: don't linearize collections in get_preimage_col_value
cdc: log: change return type of get_preimage_col_value to managed_bytes
cdc: log: remove an unnecessary copy in process_row_visitor::live_atomic_cell
cdc: log: switch cell_map from bytes to managed_bytes
cdc: log: change the argument of log_mutation_builder::set_value to managed_bytes_view
cdc: log: don't linearize the primary key in log_mutation_builder
atomic_cell: add yet another variant of make_live for managed_bytes_view
compound: add explode_fragmented
d77eb39076