Stabilize encoding v1

[IGI-111]

Now that #4769 has been implemented we should take the necessary steps to turn the experimental encoding into the default:

• Update documentation
• Improve error messages:
  • set new encoding as true by default and allow it to be disabled #5915 improves messages for types that AbiEncode/AbiDecode impl is not in scope; it can be because the type does not have one, or core is not accessible.
  • better error and dca for configurables #6121 improves messages when the necessary decode function is not in scope for configuirables.
• Implementing an empty contract gives a false warning in an autogenerated file #6016
• Resolve any known bugs (notably with SDKs)
  • fallback when all contract selectors fail #5703
  • make source id optional when auto impl for new encoding #5721
  • fix predicate entry fn #5723
  • fix auto impl removing method name log #5733
  • Contract with implicit_std set to false and no core as dependency.
  • Certify all cli commands allows --experimental-new-encoding flag
  • Encoding for configurables #5906
  • Remove raw_slice, str and others limitations of inputs and outputs.
    • Support for string slices in contracts/predicates/scripts #6079
  • Encode buffer size. Do we want limits? This set new encoding as true by default and allow it to be disabled #5915 makes the Buffer to be dynamic.
  • call_with_function_selector
• Improve performance
  • Fix for performance problem with MegaExample #5782
  • Performance stats

Actions that needs to be undone after #5915 is merged:

Enable these tests again:

• should_pass/language/name_resolution_after_monomorphization (Enable name-resolution-after-monomorphization again #5996)
• should_pass/language/shadowing/shadowed_glob_imports
• should_pass/language/name_resolution_inside_intrinsics

These seems to be a bug related with shadows and glob imports. These issues seem to point to similar issues: #5500, #5700

• sdk-harness/run_external_proxy re-enable LDC test #6240

Fix warnings of these tests

• should_pass/dca/contract/superabi_contract_calls
  What happens here is that when we implement a trait for Contract, we actually generate two functions: one prefixed __contract_entry that is called by the method selector; and another one normal, that can be called freely. So, if the trait method is never called manually, it is marked as dead.

• should_pass/dca/unused_fields
  auto-impl is making all fields being used. so no dead code warnings are being generated. We need to fix this.
  fix dca for encoding v1 autogenerated code #6006

Nice to do for future versions:

1 - Contract method selector using match on string slices, ideally desugaring into radix matching;
2 - CEI analysis running normally on "__entry". We need CEI analysis to know about Never or be smart about control flow;

• Improve the implementation to increase Buffer size dynamically. Done by Fix Bytes, Vec and String buffer ownership #6142, because the buffer intrinsic increase buffer correctly now.

• Buffer used by AbiEncode needs a push_bytes so we can be more efficient when encoding Bytes and others. This should decrease significantly gas usage in some cases. Done Encoding v1 for Configurables #5942, because we can encode slices directly now.

Encoding v1 for Configurables

• Avoid decoding configurable on each reference. Done by Faster access for configurables #6058.
• Small issue where impl AbiEncode/Decode is not in scope when calling contracts:
  Contract calls need their return method imported manually #5936

From #5942

• Enable sdk-harness tests that were ignore. SDK needs to update configurable encoding.
• Correctly error when a type with custom impl for AbiEncode is used in configurables
• abi_encode_size_hint and numeric: Today we decay Numeric into u64. This should be fixed.
• improve const_eval loops with time-based limit/warnings.
• Refactor configurable constants in IR. #4352