This adds agile encryption for OOXML documents. Previously we
always used the standard encryption used in MSO 2007 for max.
compatibility, but new MSO versions (2010+) use the agile
encryption, which allows more strong encryption methods (AES256
with SHA512). With this change we can now use do AES128 with
SHA1 or AES256 with SHA512 encryption.

In addition the agile encryption has data verification with HMAC
hashing. With this change we also now write the data verification
hash into the encrypted document and in addition also do data
verification when opening / decrypting a document, so to make sure
the document is not corrupted.

Change-Id: Ib45d397df228c355941eefb76d51e5d6f8925470
Reviewed-on: https://gerrit.libreoffice.org/56974
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>