Add keyboard shortcut to save automation/scene/script

[gilsonmandalogo]

Proposed change

Add CMD+S or CTRL+S keyboard shortcut to save automation/scene/script.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (thank you!)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example configuration

No configuration needed.

Additional information

• This PR is related to issue: Save Automation/Scene/Script with keyboard shortcut #6397

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

[iantrich]

🎉🎉🎉🎉

[bramkragten]

Can we make this a class mixing, that will call a function of the class when ctrl+s is called?

[gilsonmandalogo]

@bramkragten Thanks for your suggestions. This is my first time with LitElement, but I'll look at documentation to do this.

[bramkragten]

🎉 great!

[donkawechico]

First of all, this is awesome.

Second of all, and this is an admittedly unlikely scenario, but now that Quick Bar (with its two hotkeys) is a thing, we might want to think of ways to avoid collisions.

Some kind of shortcut registry, or at least unifying them all under a common mixin where a dev is likely to see what's already taken.

Also, might consider checking for mac OS to avoid having duplicate hotkeys (see: #7293). Standardizing our shortcuts would help this as well.

Update: Took a stab at this consolidation over here: #7314