Updated branding, email and crates

- Updated branding for admin and emails
- Updated crates and some deprications
- Removed newline-converter because this is built-in into lettre
- Updated email templates to use a shared header and footer template
- Also trigger SMTP SSL When TLS is selected without SSL
  Resolves #1641

src/static/templates/email/delete_account.hbs

@@ -5,6 +5,4 @@ Click the link below to delete your account.
 Delete Your Account: {{url}}/#/verify-recover-delete?userId={{user_id}}&token={{token}}&email={{email}}
 
 If you did not request this email to delete your account, you can safely ignore this email.
-
-===
-Github: https://github.com/dani-garcia/vaultwarden
+{{> email/email_footer_text }}