Implement Rows/Columns on Editor and Deprecate AutoSize

### Description

Currently we have a property "AutoSize" on Editor that doesn't make as much sense on MAUI. See https://github.com/dotnet/maui/pull/1202. In theory users should just specify a fixed height/width if they don't want the editor size to change as users type. .NET MAUI enables this by default whereas XF did not. The main difficulty behind specifying a fixed height/width though is making sure it measures correctly to the font so it might make the most sense to deprecate AutoSize and let users specify Rows/Columns instead

Alternative options:
- Users could just specify a max/min size on the Editor and it'll just adjust itself to the right enough size

### Public API Changes

```C#
interface IEditor
{
int Rows;
int Cols;
}
```

Deprecate `AutoSize` on controls

### Intended Use-Case

Allow users to specify a fixed height/width that's able to take into account the font size.

The issue names Editor, IEditor, and AutoSize but no files or tests. Start by locating those APIs and tracing AutoSize behavior; done requires an agreed Rows/Cols design, a defined deprecation scope, and verified font-aware sizing across the affected platforms.

Written by the indexing model from the issue text.