feat(gtest): Introduce builtins to gtest

[techraed]

1. Adds eth-bridge and bls12_381 builtins with corresponding tests. The introduced codebase almost identically copies builtins from pallet, but doesn't adapt it fully to the gtest, leaving some "obtain payload length" functionality for future gas charge feature.
2. Refactors a little bit WasmProgram trait for mock programs

The gas charging for builtins is missing and is intended to be introduced in following PRs

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
gtest/src/manager/reservations.rs	96% smaller
gtest/src/state/mod.rs	89% smaller
gtest/src/manager/journal.rs	83% smaller
pallets/gear-builtin/src/tests/bad_builtin_ids.rs	78% smaller
gtest/src/program.rs	73% smaller
gtest/src/system.rs	69% smaller
pallets/gear-builtin/src/tests/bls381.rs	65% smaller
pallets/gear-builtin/src/benchmarking.rs	55% smaller
pallets/gear-eth-bridge/src/internal.rs	41% smaller
pallets/gear-builtin/src/lib.rs	38% smaller
pallets/gear-builtin/src/mock.rs	36% smaller
gtest/src/state/programs.rs	17% smaller
pallets/gear-builtin/src/bls12_381.rs	16% smaller
gtest/src/manager/block_exec.rs	12% smaller
runtime-interface/src/lib.rs	10% smaller
gbuiltins/bls381/src/lib.rs	4% smaller
gbuiltins/eth-bridge/src/lib.rs	4% smaller
gtest/src/manager/memory.rs	1% smaller
pallets/gear-eth-bridge/src/builtin.rs	1% smaller
Cargo.lock	Unsupported file format
Cargo.toml	Unsupported file format
ethexe/common/Cargo.toml	Unsupported file format
gbuiltins/bls381/Cargo.toml	Unsupported file format
gbuiltins/eth-bridge/Cargo.toml	Unsupported file format
gtest/Cargo.toml	Unsupported file format
gtest/src/builtins/bls12_381.rs	0% smaller
gtest/src/builtins/eth_bridge.rs	0% smaller
gtest/src/builtins/mod.rs	0% smaller
gtest/src/lib.rs	0% smaller
gtest/src/manager.rs	0% smaller
gtest/src/state/bridge.rs	0% smaller
gtest/src/state/mailbox/actor.rs	Unsupported file format
pallets/gear-builtin/Cargo.toml	Unsupported file format
pallets/gear-eth-bridge/Cargo.toml	Unsupported file format
pallets/gear-eth-bridge/src/tests.rs	0% smaller
runtime-interface/Cargo.toml	Unsupported file format
utils/builtins-common/Cargo.toml	Unsupported file format
utils/builtins-common/src/bls12_381.rs	0% smaller
utils/builtins-common/src/bls12_381/high_level.rs	0% smaller
utils/builtins-common/src/bls12_381/low_level.rs	0% smaller
utils/builtins-common/src/eth_bridge.rs	0% smaller
utils/builtins-common/src/lib.rs	0% smaller
utils/crates-io/src/lib.rs	0% smaller

[StackOverflowExcept1on]

LGTM, but we should think about not being too dependent on blockchain framework and moving it into separate crates

[techraed]

@breathx @StackOverflowExcept1on both your suggestions are applied