Email message composer screen needs to closely mimic desktop client

[hexadecible]

Let's update this screen to more closely match what we're doing on desktop (see below image)

• Display the sender's avatar on the left-hand side of the metadata header
• Display the sender's email address or Display Name in bold. If no display name exists default to email, otherwise display name should take preference.
• Display the date the email was received
• Tapping the to: field should display full metadata in a container underneath the header
• Email message body should default to using and displaying bodyAsHtml. If bodyAsHtml is null, then revert to bodyAsText.