`html` and `text` templates for mailers by default
fix url connections for sqlite3
converts hashes in arrays of unfiltered params to unpermitted params [fixes #13382]
Merge pull request #13425 from kassio/master

Generates html and text templates for mailers by default.
Test with 2.1.0-rc1
refactors AC::Parameters#fetch

AC::Parameters#fetch was refactored in 7171111 to prevent self mutation, but
in doing so it hardcodes logic #convert_hashes_to_parameters is supposed to
encapsulate.

Better leave the delegation, and add a way to avoid mutating self in there.
optimizes array conversion in AC::Parameters
Fix typo [ci skip]