[1pt] memtx: varbinary supported in bitset indexes

[TarantoolBot]

memtx: varbinary supported in bitset indexes

Product: Tarantool
Since: 2.7.1
Audience/target: Tarantool users
Root document: https://www.tarantool.io/en/doc/latest/book/box/indexes/#bitset-indexes
SME: @mary3000
Peer reviewer: @

Details

Now it is possible to create bitset indexes on the fields of varbinary type,
e.g.: s:create_index('b', {type = 'bitset', parts = {1, "varbinary"}})
Requested in tarantool/tarantool@14bf2fd.