Adding Phone To helper like mail_to for handling phone numbers

Adding Phone To helper like mail_to for handling phone numbers

Useful for mobile browsers and desktop browser with phone supported software.

Creates a tel link tag to the specified +phone_number+

Accepts blocks

Should this be written as `test_phone_to_accepts_string_and_symbol_keys`? Also, we've been removing support for string keys in a lot of places, do we need to allow string keys here at all?