This commit changes the variables used to represent the size and
progress of downloads from u32 to u64. This allows `pro` and
`Browser` to report the total size and progress of a download
correctly for downloads larger than 4GiB.
`Stream` will be qualified as `AK::Stream` until we remove the
`Core::Stream` namespace. `IODevice` now reuses the `SeekMode` that is
defined by `SeekableStream`, since defining its own would require us to
qualify it with `AK::SeekMode` everywhere.
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 is the final component that required LibProtocol as a dependency
of LibWeb. With this, we can now remove the dependency, and LibWeb no
longer requires IPC to work :^)
