Rename --pruning and --keep-blocks to be more similar to one another (#11934)

* rename prunning and keep-blocks flags

* Add aliases in keep-blocks and pruning for backward compatibility

* Rename in code variables from  and  to  and

substrate/client/service/src/config.rs

@@ -19,7 +19,7 @@
 //! Service configuration.
 
 pub use sc_client_api::execution_extensions::{ExecutionStrategies, ExecutionStrategy};
-pub use sc_client_db::{Database, DatabaseSource, KeepBlocks, PruningMode};
+pub use sc_client_db::{BlocksPruning, Database, DatabaseSource, PruningMode};
 pub use sc_executor::WasmExecutionMethod;
 #[cfg(feature = "wasmtime")]
 pub use sc_executor::WasmtimeInstantiationStrategy;
@@ -79,7 +79,7 @@ pub struct Configuration {
 	/// Number of blocks to keep in the db.
 	///
 	/// NOTE: only finalized blocks are subject for removal!
-	pub keep_blocks: KeepBlocks,
+	pub blocks_pruning: BlocksPruning,
 	/// Chain configuration.
 	pub chain_spec: Box<dyn ChainSpec>,
 	/// Wasm execution method.