* CT config methods are accepting zero

* intrduce && use configuration range in CT

* Update core/client/db/src/lib.rs

Co-Authored-By: cheme <emericchevalier.pro@gmail.com>

* full PR URI

* updated next_max_level_digest_range comment

* added skewed digest description

* added comment for loop

* call next_max_level_digest_range from prev_max_level_digest_block

* more test cases

* Update core/state-machine/src/changes_trie/surface_iterator.rs

Co-Authored-By: cheme <emericchevalier.pro@gmail.com>

* updated comment