Allow the Editor to define if the host may request window sizing

[basdp]

Currently, the wrappers have the hosts requests for window resizing hardcoded to false. I propose to forward this decision to the implementation of the Editor.

Please let me know if there are any concerns or design discussions to be made.

This PR does not functionally change any existing plugins, the default is still to return false to the host when it asks if it may resize the window.

[basdp]

This PR is ready for review. Thanks for consideration! :-)

[basdp]

I'm honestly quite sad that, half a year later, nobody has acknowledged this pull request or even took the time to look at it. I would have expected an implementation for such a major missing feature would be merged rather quickly.

I've had a few people reaching out to me over the past half year about this issue asking me for help with resizing their plugin window. I've started to discourage them to use nih-plug, because I feel this framework is clearly not maintained well enough for use in serious projects.

I'm not saying my code is the holy grail for nih-plug, I'm just saying that I feel disregarded in this community and that I have started to regret the many hours spent on this PR. So far my good intentions of giving back to the open source community...

For anyone still out there looking for basic features not currently in nih-plug, I recommend writing your plugins in the CLAP framework and use their wrappers for VST3 and other formats. This also solves the licensing issue with VST3, for which CLAP-wrappers has a rather elegant solution that is legally sound.

Again, I mean no disrespect. I have come to the conclusion my goals are misaligned with the goals of the maintainers of this project. I just feel I could have had at least a "thank you for your work on this, but we don't feel this PR matches our goals/intentions/quality standard/etc".