Feature Request: debounce in ngModelOptions

[ ] Regression (a behavior that used to work and stopped working in a new release)
[ ] Bug report
[ x] Feature request
[ ] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead see https://github.com/angular/angular/blob/master/CONTRIBUTING.md#question

## Current behavior
No support for `debounce` in `ngModelOptions`

## Expected behavior
Angular doesn't yet support `debounce` `ngModelOption` on inputs. I would like to know what is the logic behind not implementing the same with `blur`?

## Example usecase for debounce:

A text input like in Google docs which should save the typed text after 3 secs of no keypress after typing.

Start by locating the ngModelOptions entry point and reviewing how the existing blur option is handled. Determine the intended debounce behavior for inputs, including how the three-second example should interact with model updates, then identify the relevant tests needed to define when the feature is complete.

Written by the indexing model from the issue text.