Compile support for SQLITE_DBPAGE

[flavorjones]

https://www.sqlite.org/dbpage.html

cc @kevinmcconnell

[kevinmcconnell]

Nice! 🎉

[flavorjones]

I may need to introduce a constant to track whether the libsqlite being used is vendored or a system library. It's useful to know when to skip the sqlite_dbpage test, but is also generally useful for the gem to be more self-descriptive for debugging purposes (e.g., Nokogiri::VERSION_INFO).