HaikuDepot: Store local package path in PackageInfo...

... when launched with a path to a .hpkg file.
HaikuDepot: Never refresh repositories or package lists...

... when in single package mode.
Package Kit: Always allocate local repository

Consequently always register it with the solver in Init(). This solves the
problem that it made a difference at which time Init() is called. Init() is
called at the beginning of Install() and Uninstall(), but HaikuDepot was
calling it before that for other reasons. A second call to Init() will exit
early. If local package files were added to the PackageManager instance,
the local repository was created lazily, but because Init() did not run a
second time, the local repository was not registered with the solver. Now
it already is, since it is no longer created on demand, but always.
HaikuDepot: Support installing local package files

 * Give the PackageManager either the package name, or the path to a local
   .hpkg package to Install().
 * Implement Warn() to at least print something to the command line. Change
   the TODO to show the warning to the user instead.
HaikuDepot: Implement ProgressPackageDownloadStarted()...

... by calling ProgressPackageDownloadActive() with a 0.0f progress
percentage.