Check input for Log length

Check input for Log length to make sure the input is a nonnegative
integer.

Change-Id: Iae3dbf4236f1c7ceb8260540dd4f9086349bc13a
Closes-bug: 1331624
Test's random name gen now uses uuid4

This test used a random integer to generate the name of a file.  Although
it doesn't pose a real problem, it's probably better just to drop a UUID
in instead of a 3-digit number, to avoid collisions.

Partially implements blueprint: selenium-integration-testing

Change-Id: I95fd2c25dc4e2e5ddc47cd390b472c8ee2310e97
Closes-Bug: 1399219
Integration tests - 3 new form fields

I added 3 new form fields, that are frequently used
in different horizon's forms:
* CheckBoxFormField - with the options to mark, unmark
and check if already marked.
* ChooseFileField - with a choose file action.
* TextAreaFormField - intended for multi-line text input box.

The reason I separated this change from the Images page patch
is to allow others to use it in their patches without forcing
the images as a dependency.

Partially implements blueprint: selenium-integration-testing

Change-Id: I94260db6089e44e66bf19b0ede172eec1756cdc5
Base Glance Metadata Definitions Admin UI

Provide a base admin UI for viewing, importing, and associating the
metadata definitions that can be used with various resource types
such as flavors, images, and host aggregates.

In Juno, Glance provided a metadata definitions catalog[1][2] where
users can register the available metadata definitions that can be used
on different types of resources (images, artifacts, volumes, flavors,
aggregates, etc). This includes key / value pairs such as
properties, extra specs, etc. Horizon landed several patches that
read these properties. You can view the functionality in the
"update metadata" action on Flavors, Images, and Host Aggregates.

This specific patch is to bring in the Admin UI for the basic coarse
grained actions on the definitions in the catalog. This includes creating
(importing) a namespace, viewing the overview details about
it, deleting the namespace, and associating the namespace for use with
specific resource types.

Future blueprints will be registered for:
 - CRUD on individual metadata definitions within the namespace
For example, editing the default value of an individual property.

[1] Approved Glance Juno Spec:
https://github.com/openstack/glance-specs/blob/master/specs/juno/metadata-schema-catalog.rst

[2] Glance PTL Juno Feature Overview:
https://www.youtube.com/watch?v=3ptriiw1wK8&t=14m27s

Co-Authored-By: Travis Tripp <travis.tripp@hp.com>
Co-Authored-By: Santiago Baldassin<santiago.b.baldassin@intel.com>
Co-Authored-By: Bartosz Fic <bartosz.fic@intel.com>
Co-Authored-By: Pawel Koniszewski <pawel.koniszewski@intel.com>
Co-Authored-By: Michal Dulko <michal.dulko@intel.com>
DocImpact: Concept awareness
Change-Id: Ie34007f73af7e0941631a52f03841068e509a72c
Implements: blueprint glance-metadata-definitions-base-admin-ui
Merge "Integration tests - 3 new form fields"
Merge "Test's random name gen now uses uuid4"
Merge "Check input for Log length"
Merge "Base Glance Metadata Definitions Admin UI"
Reduced code duplication in creating page headers

The same line of code to add a page title to a template was repeated in
many templates, this patch moves that line into the base.html, and also
tries to standardize the way page titles are defined in the python.

Change-Id: I11367d3007ebae727ba45446076a31307d477995
Closes-Bug: 1399840