* parity db subsystem without cache and no splitted column

* fmt

* fix path (auto from parity-db fail)

* lru cache for db column with cache

* Revert "lru cache for db column with cache"

This reverts commit ae177bc5e107a075eff6a21f651218ada6599b74.

* Write_lock mutex

* theoric code for bridges

* revert changes

* Revert bridge changes

* fix spec_version

* update parity db

* test purge-db

* Use specific ordered collection with paritydb.

* Revert "Use specific ordered collection with paritydb."

This reverts commit 8b66d0a4ae914cba1af0f44050d45dd6d9327c6b.

* fix chain selection tests.

* remove patch

* fix auto.

* Remove useless exists directory method

* purge chain without parity-db removal

* spellcheck

* renamings and filtering.

* fix assertion

* format

* update parity-db and fmt

* Auto keep using rocksdb when it exists.

* Revert "Auto keep using rocksdb when it exists."

This reverts commit cea49b32ae590bdce31fed5c45f3c028ae0c7564.

* Update kvdb version.