Aurindam Jana

Update Slint license to v1.2

6

* Merge the Ambassador and Commercial licenses in one agreement. * Update the terms to offer the per-Seat (Flex) and per-Product (Buyout) options

Taking inspiration from the Royalty-free license, I am considering to simplify the commercial license. This is a first draft. After incorporating your comments, we could ask Till to review it.

Based on feedback from [/slint-ui/slint/pull/3063](https://github.com/slint-ui/slint/pull/3063)