The reflection module is now part of oslo.utils so we should
remove our local version and use that version instead; this
also goes for the uuidutils module which is now part of
oslo.utils as well so we no longer need our local version
copied from the incubator...

Note that one reflection method `find_subclasses` which was to
specific to taskflow is now moved to the misc utility module
instead of its prior home in the reflection module.

Change-Id: I069881c80b0b2916cc0c414992b80171f7eeb79f

Add a new logging BLATHER level to easily allow its
usage for messages that are below the normal DEBUG level
such as compilation information and scope lookup info
which can be very verbose in logs if always enabled.

Change-Id: I828211403bd02bfd6777b10cdcfe58fb0637a52c

When a retry object is asked to make a decision about the atoms
it controls it is currently provided a complex object that contains
what has failed and why and what was provided to try to resolve this
failure as raw types. To make it easier to interact with that history
provide and use a more easier to interact with helper object that
provides useful functionality built ontop of the raw types.

Part of blueprint intuitive-retries

Change-Id: I93f86552f5a0c26b269319e4de6d9b8fb3b3b219

Internally we should be using the new location and not the
deprecated location wherever possible. This avoids emitting
warnings messages on our own code, which is a dirty habit.

Change-Id: Idac5a772eca7529d92542ada3be1cea092880e25

Move the storage ensuring logic from being split
across the engine and the storage layer and expose
only a single `ensure_atom` function that does
the work instead.

This also removes the access to the `ensure_task`
and `ensure_retry` methods as the internals of the
`ensure_atom` function is now the only location
that needs to use these two functions.

This reduces the need to do type specific atom
checks in the non-storage components (which we
want to reduce overall).

Breaking change: removes the public methods named
`ensure_task` and `ensure_retry` (which should not
be used externally anyway) from the storage object
and makes those internal/private methods instead.

Change-Id: I3a0f1f0dd777a1633b4937e16b50030275c84d1d

To complement the future changes in patterns we also want
to allow the execution of patterns to be affected in a similar
manner so that symbol lookup is no longer as confined as it was.

This change adds in the following:

- Symbol lookup by walking through an atoms contained scope/s.
- Better error messaging when symbols are not found.
- Adjusted & new tests (existing ones work).
- Better logging of the symbol lookup mechanism (helpful
  during debugging, although it is very verbose...)

Part of blueprint taskflow-improved-scoping

Change-Id: Id921a4abd9bf2b7b5c5a762337f8e90e8f1fe194

Update hacking to the new requirements version and
fix about half of the new reported issues. The other
hacking issues are for now ignored until fixed by
adjusting our tox.ini file.

This commit fixes the following new hacking errors:

H405 - multi line docstring summary not separated
       with an empty line
E265 - block comment should start with '# '
F402 - import 'endpoint' from line 21 shadowed by
       loop variable

Change-Id: I6bae61591fb988cc17fa79e21cb5f1508d22781c

Since storage injection can target atoms and not
just tasks (just one type of atom) the method naming
is more appropriate when named as atom injection (and
associated variable name changes reflect this as well).

Also add more stringent checking around the names of
atoms that are targeted for injection (ensuring that
the name provided actually exists in the storage unit).

Change-Id: I0ad0178240613fda166ea8fcdc441b37290445f8