ruby : add `Whisper::Context::Params`, fix token memory management (#3647)

ruby : add `Whisper::Context::Params`, fix token memory management (#3647)

* Don't convert to temporary VALUE

* Define Whisper::Context::Params

* Add test for Whisper::Context::Params

* Implement Whisper::Context::Params

* Add tests for Context::Params

* Fix Whisper::Token memory management

* Add test for token_timestamps

* Make Context accept Context::Params

* Make Context::Params.new accept keyword args

* Add test for Context::Params.new with keyword args

* Add signature of Context::Params

* Add example for Whisper::Token

* Fix typos

* Revert "Don't convert to temporary VALUE"

This reverts commit dee66e738491ae742fc981dc6e18ad92f1b05316.

* Hold Token#text as Ruby objectd

* Don't use pointer for ruby_whisper_context_params.params

* Use RUBY_DEFAULT_FREE instead of custom function

* Update bindings/ruby/README.md

Co-authored-by: Daniel Bevenius <redacted>
* Add document for Whisper::Context::Params

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Co-authored-by: Daniel Bevenius <redacted>