MediaReplicant: Middle button mute/unmute support

* Add mute/unmute support by clicking middle mouse button
  on media replicant;
* Fixes #7468.

- GCI 2013
HaikuDepot: Clean up how PackageInfo is populated

 * Remove the stuff from constructor, which cannot be known at the time
   (icon and changelog).
 * Added setters for those and notification handling (not yet in the
   listeners).
 * Add more PackageInfoListener flags.
 * Populate categories and dummy user ratings for "wonderbrush". This
   code was still in from testing, but the package name is actually
   different in real PM.
HaikuDepot: Update the correct view for given notification
HaikuDepot: Fixed some inconsistencies in List.h
HaikuImage*: Create missing writable dirs in ~/config

Also reduce code duplication by moving the respective code to
HaikuImageCommon.
dump_mapping_info(): Remove problematic initializer

Fixes gcc 2 build.
x86/paging: Do not use array placement new

Array placement new has implementation defined memory overhead what
makes it pretty useless.
Add an icon for Open Cubic Player (ocp)

The best I could do, feel free to fix.
Reintroduce BUrlResult and add BDataRequest

* BUrlResult is back, with ContentType and Length methods.
* BHttpResult subclasses it and use HTTP header fields to implement
those
* Introduce BDataRequest for "data" URIs. These embed the data inside
the URI, either as plaintext or base64 encoded.
Update HaikuWebkit to version 1.2.1.

* This fixes the crash on trying to download something, and has some new
features as well.
BHttpRequest::Result() returns a BUrlResult&.

This overrides BUrlRequest::Result. The returned reference points to a
BHttpResult and can be cast by callers.
StyledEdit/DiskUsage/DriveSetup post-hrev46520 fixes

* StyledEdit - make Find/Replace windows non zoomable, select the search
  string view on showing the window for repetitional search;
* Devices - fix plain property list background - to standard one and
  restore read-only state of this pane;
* DriveSetup - remove radio-mode of drive list context popup menu;
* DiskUsage - SetLowColor to parent background to avoid small text
  rendering issue.

Many thanks to Sergei Reznikov for testing and pointing issues out.
Minor updates to BListView docs
Updates to BOutlineListView for docs

mostly param naming.

No functional change intended.
Add docs for BOutlineListView class
kernel/cpu: Do not use get_system_info() to identify CPU
kits/media: CPU clock speed may vary significantly
bin/top: Remove busy_wait_time
libroot: Add prototypes for __{get,set}_scheduler_mode
libroot: Fix uninitialized counter in mutex_lock()