This class had slightly confusing semantics and the added weirdness
doesn't seem worth it just so we can say "." instead of "->" when
iterating over a vector of NNRPs.
This patch replaces NonnullRefPtrVector<T> with Vector<NNRP<T>>.
We have a new, improved string type coming up in AK (OOM aware, no null
state), and while it's going to use UTF-8, the name UTF8String is a
mouthful - so let's free up the String name by renaming the existing
class.
Making the old one have an annoying name will hopefully also help with
quick adoption :^)
This utilises LibIMAP and LibWeb to provide an e-mail client.
The only way currently to connect to a server and login is with a
config file. This config file should be stored in ~/.config/Mail.ini
Here is an example config file:
```
[Connection]
Server=email.example.com
Port=993
TLS=true
[User]
Username=test@example.com
Password=Example!1
```
Since this is stored in plaintext and uses a less secure login method,
I'd recommend not using this on your main accounts :^)
This has been tested on Gmail and Outlook. For Gmail, you either have
to generate an app password if you have 2FA enabled, or enable access
from less secure apps in your account settings.
