Support heap types (Vector, Bytes, StdString) return from scripts

[camsjams]

Motivation

Requirements:

• Vectors can be returned from Contracts Improve Vector output support with Vec<> return #933
• Bytes can be sent and returned from Contracts Add support for the new stdlib type Bytes and RawSlice for inputs and outputs for Contracts #1188
• Vectors can be sent to Scripts feat: support Vector input for Scripts, improve overall Vector input support #1046
• Bytes/RawSlices can be sent to Scripts Support Bytes and RawSlice input for Scripts #1274
• StdStrings can be sent and returned from Contracts Support dynamic String type for Contracts, Scripts, and Predicates #1276

See also: FuelLabs/fuels-rs#866

Usage example

No response

Possible implementations

• Add return for Vectors for Scripts
• Add return for Bytes for Scripts
• Add return for RawSlice for Scripts
• Add return for StdStrings for Scripts

[Dhaiwat10]

Partially blocked: FuelLabs/fuels-rs#866 (comment)

[Voxelot]

only remaining work here is for RawSlice

[danielbate]

This was fixed by #2050. As @Voxelot mentions there is still an issue with raw_slice, however we have that tracked individually in #1344. So will close this issue.