This commit removes the wake lock activation toast along with the
enable/disable buttons, implementing the wake lock implicit activation
behavior. The wake lock feature is implicitly activated if the
`defaultSettings.application.wakeLock` in the `settings.yml` file is set
true. For mobile devices that do not support the API or fail when
requesting a wake lock, toasts are raised explaining that calls will be
dropped when the screen turns off.
In cases where `defaultSettings.application.wakeLock` is set false, users
can enable the wake lock manually through the settings menu.
Adds wake lock feature, which is available only for mobile users using
browser with support to the given API.
When an user using a supported device joins the meeting, a toast is
displayed offering to activate the feature.
Adds a toggle under settings menu to activate/deactivate it.
