(doc) Add documentation for environments api call

The environments resource was updated but documentation was not changed
to reflect the changes.

This commit adds the documentation to describe new functionality.
(PUP-2999) Use host.tmpdir for agent tmpdirs

PUP-2999 switched these two tests to use Beaker's new
create_tmpdir_for_user() helper, but this has a bug related to windows
acceptance (QENG-1108) in that it doesn't end up prepending a 'cmd.exe
/c' and we get pathing issues with our current acceptance setup on
windows.

Just switching back to using host.tmpdir calls for now; the original
changes were for jvm-puppet, but that is master only, and these are
agent calls.
Merge branch 'issue/master/pup-2999-agent-tmpdirs-on-windows'

* issue/master/pup-2999-agent-tmpdirs-on-windows:
  (PUP-2999) Use host.tmpdir for agent tmpdirs
Merge pull request #2994 from demophoon/maint/master/fix-http-environment-doc

(doc) Add documentation for environments api call
(PUP-1044) Ensure file bucket streams are closed at all times after use

This makes the stream() method on file bucket file take a block
to ensure that the processing of the stream always ends up closing it.
Merge pull request #2999 from hlindberg/PUP-1044_ensure-closed-filebucket-file

(PUP-1044) Ensure file bucket streams are closed at all times after use