seal_delegate_call api function (support for library contracts) (#10617)

* seal_call_code implementation

- tests
- benchmark

* Addressing @xgreenx's comments

* Fix test-linux-stable-int

* Rename seal_call_code to seal_delegate_call

* Pass value unchanged into lib contract

* Address @athei's comments

- whitespace .wat issues
- wrong/missing .wat comments
- redundant .wat calls/declarations

- change order of functions (seal_delegate_call right after seal_call)
  in decls, tests, benchmark
- fix comments, move doc comments to enum variants
- remove unnecessary empty lines

- rename runtime cost DelegateCall to DelegateCallBase
- do not set CallFlags::ALLOW_REENTRY for delegate_call

* Do not pass CallFlags::ALLOWS_REENTRY for delegate_call

* Update comment for seal_delegate_call and CallFlags

* Addressing @athei's comments (minor)

* Allow reentry for a new frame after delegate_call (revert)

* Same seal_caller and seal_value_transferred for lib contract

- test
- refactor frame args due to review
- logic for seal_caller (please review)

* Put caller on frame for delegate_call, minor fixes

* Update comment for delegate_call

* Addressing @athei's comments

* Update weights generated by benchmark

* Improve comments

* Address @HCastano's comments

* Update weights, thanks @joao-paulo-parity

* Improve InvalidCallFlags error comment

substrate/frame/contracts/src/lib.rs

@@ -570,6 +570,8 @@ pub mod pallet {
 	pub enum Error<T> {
 		/// A new schedule must have a greater version than the current one.
 		InvalidScheduleVersion,
+		/// Invalid combination of flags supplied to `seal_call` or `seal_delegate_call`.
+		InvalidCallFlags,
 		/// The executed contract exhausted its gas limit.
 		OutOfGas,
 		/// The output buffer supplied to a contract API call was too small.