ruby : make Ruby bindings installed with build options (#3056)

ruby : make Ruby bindings installed with build options (#3056)

* Fix signature of URI.new7s return value

* Use path instead of string | _ToPath

* Add document comment to RBS

* Remove unnecessary build flags

* Remove unnecessary line

* Remove files have become unnecessary

* Make gem install accept build options for whisper.cpp

* Add instraction for build options in README

* Add methods for check to Options

* Test build options

* Rename: configs -> options

* Add assert_installed assertion

* Use assert_installed

* Remove unused attribute

* Extract dependency check logic as Dependencies class

* Update README

* Add WHISPER_FFMPEG option

* Test extra build options only on local test

* Bump version to 1.3.2 [skip ci]