The `patricia_trie` crate is generic over the hasher (by way of HashDB) and node encoding scheme. Adds a new `patricia_trie_ethereum` crate with concrete impls for Keccak/RLP.
* Update `add_license` script
* run script
* add `remove duplicate lines script` and run it
* Revert changes `English spaces`
* strip whitespaces
* Revert `GPL` in files with `apache/mit license`
* don't append `gpl license` in files with other lic
* Don't append `gpl header` in files with other lic.
* re-ran script
* include c and cpp files too
* remove duplicate header
* rebase nit
* apply contract constructors at spec load time
* debugging
* do trie updates in two stages
* add lint exception to newly-dead constructor
* squash warning in RPC tests
* kill dead accountdb constructors
* restore accountdb constructors under test configuration
* use provided state root in spec, if it exists
* Actually enable fat db, and do RPCs for it.
* Implement HashDB traits for AccountDB.
* user defaults
* finished user defaults
* user defaults are network-dependent
* added tests for newly added functions, logger is initialized first
* dir cleanup in progress
* user_file is placed next to snapshots
* fixing requested change
* optionally use no mangling for accountdb
* add the recorder module
* get_recorded for tries, no virtual dispatch on readonly tries
* add recording test
* partially done alternate migration scheme
* finish altering migration framework
* migrate tests to new migration framework
* address comments
* remove superfluous newline
[ci skip]
* TempIdx -> TempIndex
[ci skip]
* modify account_db to work on address hash, not address
* add a database migration for new accountdb
* preserve first 96 bits of keys when combining
* handle metadata keys in migration and preserve first 96 bits
* fix comments and hash address instead of hash
* different migrations based on pruning
* migrations mutably borrow self
* batch abstraction for migration
* added missing licence headers
* overlay recent v7 migration
* better error handling, migrate version key as well
* fix migration tests
* commit final batch and migrate journaled insertions
* two passes on journal to migrate all possible deleted keys
