docs(readme): fix incorrect title in ToC

fix(module): reduce log level of absent LMDB tag (#49)

KAG-3093

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Co-authored-by: Datong Sun <[email protected]>

feat(prefix): prefix based lookup feature (#48)

This facilitates efficient enumeration of keys starting with a common prefix.

Previously a index key will need to be created, with this PR it is no longer
needed and it is possible to lookup all keys starting with a common prefix
using an iterator.

KAG-2984

feat(module): remove page level encryption

This feature is unmaintained in upstream LMDB and has known issues that prevents it from being used.

style(module): code refactoring and style cleanup

chore(actions): fix incorrect default branch name

feat(*) change lmdb_encryption_key_data to lmdb_encryption_key (#19)

change lmdb_encryption_key_data to lmdb_encryption_key,
which refers to a key file in the disk.

change lmdb_encryption_type to lmdb_encryption_mode.