This adds the possiblity to define several clusters in a Bigtable instance,
which enables replication in Bigtable.
Some of the configurations options are moved inside a `map` that defines the
properties of each cluster.
These changes alter the interface of the module, so any previous code using this
module will have to adapt to the new options interface.
We always use the same directory for terraform fixtures, so it's quite
easy to figure out its path from a pytest fixture by inspecting the
stack. This commit implements this functionality and decreases the
amount of boilerplate needed to write a test.
(Ported from fast)
Israel Herraiz
Julio Castillo
Simone Ruffilli
Ludovico Magnocavallo