Works for Gutenberg and option-pages

[jhotadhari]

• Changed script to target #wpwrap if #post is not existing. #wpwrap exists on Gutenberg and option-pages.
• Changed conditions whether the script will be enqueued or not.
• Added filter cmb2_conditionals_enqueue_script. Possibility to skip or force enqueuing of the script.
• Added filter cmb2_conditionals_enqueue_script_src. Possibility to change script source.

might solve issues:

• Not working on theme options page #55
• Any reason not to support option pages? #57
• Gutenberg Compatibility #64
• WordPress 5 - conditionals don't work. Any ideas? #65

[jcchavezs]

Thanks @jhotadhari