xfs: minimised disk seeks for node xattrs

- Made GetNext() function in Node Attributes efficient by reducing disk seeks to number of Node entries

Change-Id: I4e2bf8fb1898676c30eca2c6d6f39dc1999ae2f8
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5612
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

xfs: make static methods of abstract class instead of separate functions

Create() and Size() functions are now static methods of its corresponding abstarct class instead of separate functions

Change-Id: Iae15b8f2985843afe23fecdf49b1fcf6f7104e52
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5703
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

xfs: make common lower bound function for calculating index of Hash

Change-Id: I5e902031b0e2a1051a7f96ab94dca0dba0ca9112
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5698
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

xfs: Node xattrs

- Implemented node based extended attributes support

- Both Versions of xfs node based extended attributes can be read now

Change-Id: I2d2915029435e7722cf463b1e2b5579b361dd592
Reviewed-on: https://review.haiku-os.org/c/haiku/+/5606
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>