Display action column buttons on single line

Fixed actions column buttons to be displayed on a single line by
setting the td.actions_column width to 1em so the column dynamically
adjust, but by setting width to 1em (vs 0) stops tables with less
columns(Host Aggregates for example) having their actions column
expand overally wide, and by changing td.actions_column .btn-group
display to inline-flex.

Change-Id: I7dcb338f9f82e4b6eb88894068a9c4fb9879cf80
Closes-Bug: #1349615
Integration tests - switch_window method

I added the switch_window method to pageobject, so that it can be
used by all pages.
The method switches focus between the webdriver windows.
Args:
- window_name: The name of the window to switch to.
- window_index: The index of the window handle to switch to.
If the method is called without arguments it switches to the
last window in the driver window_handles list.
In case only one window exists nothing effectively happens.
Usage:
page.switch_window('_new')
page.switch_window(2)
page.switch_window()

The motivation of writing it was to prevent the inconsistencies
encountered lately, and the common use of a deprecated similar method.
It is not meant for handling pop-ups.

I also modified test_dashboard_help_redirectionת so it now uses
the switch_window method.

Partially implements blueprint: selenium-integration-testing
Closes-Bug: #1354824

Change-Id: Ic90accc37af292994656e1b65ad5c8527b50aaed
Add plus icon on AddDHCPAgent button

Change-Id: I4c42979b5769fb09701ceac70ccf6195f6c705c3
Closes-Bug: #1398725
Merge "Add plus icon on AddDHCPAgent button"
Merge "Integration tests - switch_window method"
Merge "Display action column buttons on single line"