luci-theme-material: make luci-app-commands command box align with Bootstrap theme

The current implementation made the commands from the app luci-app-commands absolutely positioned which resulted in hiding elements which was underneath it, ie. the buttons. This implementation removes the absolutely positioned behavior making the buttons visible again and as an upside aligns it with how the Bootstrap theme handles commands.

Signed-off-by: Daniel Nilsson <daniel.nilsson94@outlook.com>