Use upstream rocksdb (#11248)

* Use upstream rocksdb

…by way of https://github.com/paritytech/parity-common/pull/257 by @ordian.

* Hint at how `parity db reset` works in the error message

* migration-rocksdb: fix build

* Cargo.toml: use git dependency instead of path

* update to latest kvdb-rocksdb

* fix tests

* saner default for light client

* rename open_db to open_db_light

* update to latest kvdb-rocksdb

* moar update to latest kvdb-rocksdb

* even moar update to latest kvdb-rocksdb

* use kvdb-rocksdb from crates.io

* Update parity/db/rocksdb/helpers.rs

* add docs to memory_budget division

util/migration-rocksdb/tests/tests.rs

@@ -116,7 +116,7 @@ impl Migration for AddsColumn {
 	fn migrate(&mut self, source: Arc<Database>, config: &Config, dest: &mut Database, col: Option<u32>) -> io::Result<()> {
 		let mut batch = Batch::new(config, col);
 
-		for (key, value) in source.iter(col).into_iter().flat_map(|inner| inner) {
+		for (key, value) in source.iter(col) {
 			batch.insert(key.into_vec(), value.into_vec(), dest)?;
 		}