btrfs-progs: add README to kernel-shared tracking the progress

Signed-off-by: David Sterba <dsterba@suse.com>

kernel-shared/README.md

@@ -0,0 +1,55 @@
+Shared sources with kernel
+--------------------------
+
+Status and progress of kernel/userspace synchronization.
+
+- accessors.c - done, local changes
+- accessors.h - done, local changes
+- async-thread.c - done
+- async-thread.h - done
+- backref.c - todo
+- backref.h - todo
+- compression.h - done
+- ctree.c - partial
+- ctree.h - partial
+- delayed-ref.c - partial
+- delayed-ref.h - partial
+- dir-item.c - partial
+- disk-io.c - todo
+- disk-io.h - todo
+- extent\_io.c
+- extent\_io.h
+- extent-io-tree.c - done, local changes
+- extent-io-tree.h - done, local changes
+- extent-tree.c - todo
+- file.c - todo
+- file-item.c - todo
+- file-item.h - partial
+- free-space-cache.c - not needed
+- free-space-cache.h - not needed
+- free-space-tree.c - partial
+- free-space-tree.h - partial
+- inode.c - todo
+- inode-item.c - partial
+- locking.c - done, local changes
+- locking.h - done, local changes
+- messages.c - done, local changes
+- messages.h - done, local changes
+- misc.h - done
+- print-tree.c - partial, sync to kernel
+- print-tree.h - partial
+- root-tree.c - partial
+- root-tree.h - done
+- send.h - done
+- transaction.c - todo
+- transaction.h - partial, local changes
+- tree-checker.c - partial, local changes
+- tree-checker.h - partial, local changes
+- tree-mod-log.h - done, local changes
+- ulist.c - done
+- ulist.h - done
+- uuid-tree.c - partial
+- volumes.c - todo, local changes
+- volumes.h - todo, local changes
+- zoned.c - todo
+- zoned.h - todo