Simplify/Split auth_controller

[nelsonic]

As noted by @SimonLab in the PR #159 the auth_controller is way too big.
The file is currently 507 lines. This is far too long.

auth/lib/auth_web/controllers/auth_controller.ex

Lines 497 to 507 in 76c0161

	@doc """
	`logout/2` logs the person out of their session and destroys cookie.
	"""
	def logout(conn, params) do
	conn
	# |> Auth.Session.end_session()
	|> AuthPlug.logout()
	|> put_flash(:info, "Successfully logged out.")
	|> index(params)
	end
	end

Todo

• Review the file and determine if we can extract generic/helper functions
• Extract email+password related auth code into its own file, filename at your discretion.
• Remove OAuth (Google / GitHub) related code

[nelsonic]

Gonna do this as part of #207 👌