Show window on new messages

### Description

In our company, people often have lots of applications running on their PC or Tablet, and many even hide their task bar. This results in messages going unnoticed for hours, despite the red notification icon, because people often leave their desk to speak to colleagues, print something and so on, and miss the desktop notification. Many of our workstations also have no audio.
Our idea is an option to show Element on receiving new messages (if notifications are enabled for that channel) and switch to that channel, maybe optionally bring it to the front of all other windows. This way, when an employee returns to his desk, he can't miss his new message. The feature should also work on a locked Windows computer, as many people lock their PC when they leave it. Privacy should not be a problem this way, furthermore our company policy states that Element is only to be used for work related communication.
We understand that bringing the window to the front would interrupt the current workflow, so that feature should be strictly optional and disabled by default.

### Steps to reproduce

Feature request.

### Version information

- **Platform**: Desktop
- **OS**: mostly Windows 10 Pro
- **Version**: 1.7.11