`watch`: add interface groups

[ragunathjawahar]

At the moment, the watch command only has the following groups.

For Android classes:

1. Methods
2. Fields
3. Android Methods
4. Android Fields

For non-Android classes:

1. Methods
2. Fields

Add the ability to group methods by interfaces. For example, if we have the following interface while inspecting a class from an Android app,

interface MyView {
  fun showProgress(visible: Boolean)
  fun onUsernameClicked(username: Username)
}

The inspector should show an additional group:

1. Methods
2. Fields
3. Android Methods
4. Android Fields
5. MyView