Each window now has an associated progress integer that can be updated
via the SetWindowProgress IPC call.
This can be used by clients to indicate the progress of ongoing tasks.
Any number in the range 0 through 100 indicate a progress percentage.
Any other number means "no progress"
It's a little sad having two diferent versions of this function, but I
don't know of any better way to do it. This also gets rid of some const
casts down the line.
This commit moves the clipboard from WindowServer into a new Clipboard
service program. Clipboard runs as the unprivileged "clipboard" user
and with a much tighter pledge than WindowServer.
To keep things working as before, all GUI::Application users now make
a connection to Clipboard after making the connection to WindowServer.
It could be interesting to connect to Clipboard on demand, but right
now that would necessitate expanding every GUI app's pledge to include
"unix" and also unveiling the clipboard portal, which I prefer not to.
It didn't feel right to have a "DHCPClient" in a "Servers" directory.
Rename this to Services to better reflect the type of programs we'll
be putting in there.
