sstableloader: Handle non-prepared batches with ":" in identifier names
sstableloader: Handle non-prepared batches with ":" in identifier names

Because non-prepared batch statements cannot handle named variables,
we do variable replacement in this mode (terrible, yes). The regex
match does not deal with column/keyspace/table identifiers containing
":" (i.e. alternator).

Need to do boundary match (lookahead/lookbehind).

Closes #242
Fixes #230
Fixes #24l
Refs https://github.com/scylladb/scylla/issues/8230

scylladb/scylla-tools-java,scylladb/scylla-tools-java,scylladb/scylla-tools-java,scylladb/scylla-tools-java