sstables: import TimeWindowCompactionStrategy.java
sstables: import TimeWindowCompactionStrategy.java

it will be later converted to C++. Imported from latest scylla-
tools-java repository. Checked that it doesn't lack anything.

Signed-off-by: Raphael S. Carvalho <1e2942cea40e3b4d2162dfcd9e53e41c05a84d22@scylladb.com>

scylladb/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla