repair_test: rework to remove levels of indirection

The commit is large but does not introduce any semantic change and
consists primarily in code moving around, re-indented and removed.

Replace functions generating functions by functions and sequentially
iterating over a list of functions with a sequential call to the
functions.

Replace the setup/teardown with an equivalent using a with
statement and the ceph_manager.pool method.

Replace inline code with a call to ceph_manager.wait_for_all_up

It makes it easier to modify the tests, for instance to create erasure
coded pools and tests specific to them.

Signed-off-by: Loic Dachary <ldachary@redhat.com>