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
Merge "Display action column buttons on single line"