AddOnManager: remove useless traces

These were acceptable in media kit log, but are only annoying now that
the AddOnManager is ran in applications. Moreover, these get to stdout
and make some WebKit tests fail.
Update HaikuWebkit to 1.3.0.
Network Kit: Prepare for HTTP range requests

* The DataReceived hook gets a position argument, making it possible for
listeners to handle out-of-order data (from two range requests at
different positions, for example)
* Adjust HaikuDepot (only user of the API in our sources)
* Add a copy constructor to HTTPRequest that copies the relevant
parameters from an existing request. Makes it easy to repeat a request
with a different range. Could be useful for restarting downloads, or
paralellizing them.
* Add SetRangeStart, SetRangeEnd calls to HTTPRequest, no implementation
yet. I'm putting all the API changes in this commit as it needs to be
synced with a matching haikuwebkit release.
* All archs must update to HaikuWebkit 1.3.0. Previous versions are
broken by this.
AddOnManager: remove more annoying traces.
Fix build.