[Proposal] Allow users to change IMAP account settings after account creation

[chenseanxy]

Describe the solution you'd like
Currently IMAP account settings are not changable after account creation. Useful usecases are:

• Changing account password, (or reissuing IMAP-specific passwords for 2FA accounts)
• Changing IMAP server settings, eg. site migration needs a different IMAP hostname
• Other settings that might need to be changed in the future, eg. pull interval if that ever becomes a thing

I think it should be possible to reuse AdvancedImapSetupPage, since this is the page that contains everything a user would want to edit.
OnNavigatedTo would need to accept a new set of params passed from AccountDetailsPage, then pass this along to service for DB updates

Is your proposal implemented in Windows Mail?
Yes (TODO: Screenshot)

Additional context
None

[chenseanxy]

This is probably lower priority than IMAP autodiscovery stuff, I think I'm gonna do that first