[contracts] Add integrity checks by pallet hook (#12993)

* integrity test for MaxCodeLen and CallStack::len()

* integrity test for MaxDebugBufferLen

* addressed review comments

* fix append_debug_buffer()

* ci fix

* updated code_len_limit formula after further discussion

* enlarged mem safe margin after discussion

* +doc to Config trait associated types

* Apply suggestions from code review

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

* more lil fixes from code review feedback

* lowered max call depth to satisfy mem limits

* fix node runtime pallet params to satisfy integrity check

* fix max call depth value calc

Co-authored-by: Alexander Theißen <alex.theissen@me.com>

substrate/frame/contracts/src/schedule.rs

@@ -134,9 +134,6 @@ pub struct Limits {
 	/// The maximum length of a subject in bytes used for PRNG generation.
 	pub subject_len: u32,
 
-	/// The maximum nesting level of the call stack.
-	pub call_depth: u32,
-
 	/// The maximum size of a storage value and event payload in bytes.
 	pub payload_len: u32,
 }
@@ -532,7 +529,6 @@ impl Default for Limits {
 			table_size: 4096,
 			br_table_size: 256,
 			subject_len: 32,
-			call_depth: 32,
 			payload_len: 16 * 1024,
 		}
 	}