* wallet: update lmdb from store crate, migrate single backend from trait to struct, update tests cargo deps and design doc
* backend: do not panic on iter and directory creation
* return iterator errors
* build: update to last node revision
* fix: height selection for scan, remove unused mutability for wallet
* wallet: remove unused mutability conversion
* tx: store slate state at database
* build: cargo fmt
* fix: do not return error when slate not found on tx slate state update
* lmdb: do not collect all tx log records at iterator, show read errors at log
* fix: save slate state, return error if slate not found
* tx: specify amount of bad txs on slate state update error
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Co-authored-by: Joerg <wiesche89@googlemail.com>