Add option to disable server password fields

Not many hypervisors support setting a server admin password via Nova.
This change adds an item to OPENSTACK_HYPERVISOR_FEATURES called
'can_set_password' that controls whether password settings fields
are displayed in the UI.

Change-Id: I03399c171b2b7cbf756292cee283419d6235461f
Closes-bug: #1250713
Enhancements of line-chart

- Adding settings to linechart
  - all parts are configurable now, so it can be used e.g. as smaller
    version for sparklines
  - auto_size and auto_resize are now configurable
  - added option for static y axis, drafted how it will be done
    for static x axis

- Added inline documentation of each function and method

Implements blueprint horizon-reusable-charts

Change-Id: I4352bc7946d3141bacc1c964de61e55a42521da6
Heat Stack name is missing form validation.

When creating a stack using Horizon, the form is missing name
validation, so a generic error is shown whenever the name
does not follow the regex used by Heat.
([a-zA-Z][a-zA-Z0-9_.-]*)
Add server side validation and the right error message.

Change-Id: I7a639bcf96b7c74760123b6106aab7d9311f5e2f
Closes-Bug: #1254212
Merge "Enhancements of line-chart"
Merge "Heat Stack name is missing form validation."
Merge "Add option to disable server password fields"