Improve description and example of data storage endpoint

[roesekoSICKAG]

It is not clear how and if the header information should be into the data storage object. Please improve the description in that regards.

[roesekoSICKAG]

Discussion in WG meeting (2024-11-04):

• Please remove the iolinkRevision property from the datastorage object since it is useless. (For Datastorage it is mandatory to have IO-Link revision 1.1)
• Add functionID (see Table G.2 of IO-Link Interface and System Specification Version 1.1.4 June 2024)

[roesekoSICKAG]

Discussion in WG meeting (2024-11-27):

• the current solution is not very suitable for empty data storage objects
• furthermore the header information are also part of the base64 content

Decision:

• remove header from POST request payload -> two schemas for GET and POST
• change the content of the "empty data storage object" to be a 12 byte long data stream base64 encoded
• deviceId, vendorId, functionId, checksum should be 0 (basically the same information returned by the SMI)