Split message code into Local/Remote

The remote network code does not need to be aware of concepts like
Accounts etc.
Avoid cast
Naming
Move SSL code into package
Remove Preferences dependency
Move things into local
Local messages
Break dependencies
Move local message code to local package

 + cut some helper dependencies
Fix LocalMessage equality/hash
Naming
Fix test location
getUuid() -> getAccountUuid()
local -> mailstore
Remove URLEncodingHelper dependency
Tidy responsibilities
MimeUtility / Message refactor

 * break MimeUtility class into manageable pieces (MessageExtractor/CharsetSupport)
 * move HTML related code out of the mail package
Remove unused method
WS / visibility
Cleanup