Replace legacy row_filters with data client row_filters

Both the legacy and data client have row_filter files, containing a set of filter classes. ([old](https://github.com/googleapis/python-bigtable/blob/main/google/cloud/bigtable/row_filters.py), [new](https://github.com/googleapis/python-bigtable/blob/main/google/cloud/bigtable/data/row_filters.py)). The new client used the old one as a starting point, so they should be mostly consistent, but you should verify that nothing breaks as part of the change ([diff here](https://diff.googleplex.com/#key=DA0hOKS1El3A))