clarify default profiles and functions

New Feature

What does this MR do?

This is a UX improvement to make it clear that the default profile and the default function are non-selectable and non-editable. The default function's name has also been adjusted to display as "Default Function", as Identity was not clear at all. Identity is still the name of the base function type.

Related issues

Relates to #232 (closed)

Checklist

• Application works as expected when running from source
• There are dependency changes
• Liquidctl device mock tests are successful (if applicable)
• Any needed documentation changes have been made
• This MR is ready to be merged