package: Suppress version mismatch errors where V1 is supported

* Add flags parameter to Init() of BPackageReader and friends.
* Introduce flag B_HPKG_READER_DONT_PRINT_VERSION_MISMATCH_MESSAGE and
  don't print a version mismatch error when given.
* package extract/list: Use the new flag.
packagefs: PackageFile::DataAccessor: Avoid unnecessary locking

... in case of version 2 package files.
PackageFileHeapAccessorBase: Fix error output
packagefs: Fix attribute indexing

Since the package nodes' attributes are indexed before the VFS has
accessed any of its nodes, the package wasn't open and reading the
attribute data would fail. We do now open the package explicitly in
UnpackingAttributeCookie::IndexAttribute(). Moreover, as an
optimization, we also open the package in Volume::_AddPackageContent(),
so the package file isn't repeatedly opened and closed as its nodes are
being registered.
packagefs: Add caching for the package file heap reader

* ReaderImplBase:
  - Add virtual CreateCachedHeapReader() which can create a cached
    reader based on the given heap reader.
  - Rename HeapReader() to RawHeapReader() and add HeapReader() for the
    cached heap reader.
  - Add DetachHeapReader() to allow a clients to remove the heap
    reader(s) after deleting the ReaderImplBase object.
* packagefs:
  - Add CachedDataReader class, which wraps a given
    BAbstractBufferedDataReader and provides caching for it using a
    VMCache. The implementation is based on the IOCache implementation.
  - Use CachedDataReader to wrap the heap reader. For file data that
    means they are cached twice -- in the heap reader cache and in the
    file cache -- but due to the heap reader using a VMCache as well,
    the pages will be recycled automatically anyway. For attribute data
    the cache should be very helpful, since they weren't cached at all
    before.