Always loading the raw template in situations where we didn't need it -
e.g. in identify_stack, where we just want the name + id (given one of
them), or when getting the summary stack list - uses up DB bandwidth and
memory unnecessarily.
This partially reverts commit 3ab0ede98c.
* The eager_load option to get_stack() is reinstated, but with the default
flipped to True. In places where we explicitly do not want to load the
template, we pass False.
* stack_get_by_name() no longer eagerly loads the template. There were no
instances of this where we subsequently use the template.
* stack_get_all() acquires an eager_load option, with the default set to
False. Direct users of objects.stack.Stack.get_all() will not eagerly
load by default, but users of engine.stack.Stack.load_all() will get the
template eagerly loaded. This practically always corresponds to what you
want.
Change-Id: I1f156c25ea26322be5b606a61dd77d80cadd65fc
Related-Bug: #1626675
260b79ed28