CephFSDocumentsProvider: support change notification

CephFSDocumentsProvider: reduce stat call on dir listing

CephFSDocumentsProvider: support simple delete

TODO reduce stat call, notify list changes

CephFSDocumentsProvider: cheaper getDocumentType

CephFSDocumentsProvider: buildDocumentRow: refactor to column-central

more readable and easier to maintain column support this way, also
consider only wanted columns

CephFSDocumentsProvider: refactor documentId handling

CephFSDocumentsProvider: fix file creation

CephFSDocumentsProvider: disable root summary

CephFSDocumentsProvider: support thumbnail-from-exif

CephFSDocumentsProvider: mime-from-ext: remove lowercasing

libcore does this

MetadataReader: extract all with type mappings

CephFSDocumentsProvider: icon for symlink-to-dir

based on material symbols drive file move, with color from pixel

CephFSDocumentsProvider: icon for broken symlink

based on materl symbols "link off"

CephFSDocumentsProvider: use summary to show broken symlink

CephFSExecutor: preserve FileNotFoundException

CephFSExecutor: cursor extra: fallback to class name if msg empty

MediaMetadataReader: video location support

CephFSDocumentsProvider: safer permission checks

CephFSDocumentsProvider: fix java side permission check

CephFSDocumentsProvider: support rstats-via-metadata

defined in aosp and filled by fs-based provider, although nobody reads
it yet