Support for multi-values and large pages

[matthieugras]

• Implement support for multi-values, including handling of long values. This is particularly useful for cases like the AD DB, where ATTc0 (objectClass) always uses multi-values.
• Add support for the large page format. This resolves an issue in the Windows.edb test case that is caused by the fact that the new format includes the header byte of tagged values, regardless of the ExtendedInfo flag.
• Refactor long-value and compression handling to decode values based on flags instead of using heuristics.

[CLAassistant]

All committers have signed the CLA.

[scudette]

Thanks!