[2.12] Add Support for `delete` Mode

[ihnorton]

[nguyenv]

One thing I am unsure about with the delete API design as I have it is you need to use __getitem__ in order to actually submit the query:

with tiledb.open(path, "d", timestamp=3) as A:
    A.query(attr_cond=tiledb.QueryCondition("ints == 1"))[:]

Whereas this won't do anything and just creates a PyQuery object but would make more sense for deletes because we aren't actually getting anything back:

with tiledb.open(path, "d", timestamp=3) as A:
    A.query(attr_cond=tiledb.QueryCondition("ints == 1")

[nguyenv]

One thing I am unsure about with the delete API design as I have it is you need to use __getitem__ in order to actually submit the query:

with tiledb.open(path, "d", timestamp=3) as A:
    A.query(attr_cond=tiledb.QueryCondition("ints == 1"))[:]

Whereas this won't do anything and just creates a PyQuery object but would make more sense for deletes because we aren't actually getting anything back:

with tiledb.open(path, "d", timestamp=3) as A:
    A.query(attr_cond=tiledb.QueryCondition("ints == 1")

I've modified this to make it so that the latter does do a delete without needing to apply the regular indexer.

[ihnorton]

Replaced by #1388