Support for new nft types

[tanghel]

Reasoning

• In the upcoming protocol release, we have additional NFT collection types related to dynamic NFTs and NFT v2, which need accomodation at api level

Proposed Changes

• In order to make the transition as smooth as possible and avoid breaking all dapps that perform queries on the collections and nfts endpoints, the new types are mapped on the existing types NonFungibleESDT, SemiFungibleESDT and MetaESDT, with a subType attribute differentiating the new types

How to test (testnet)

• /collections should return also collections of subType NonFungibleESDTv2
• /collections?type=NonFungibleESDT should return also collections of subType NonFungibleESDTv2
• /nfts should return also NFTs of subType NonFungibleESDTv2
• /nfts?type=NonFungibleESDT should return also NFTs of subType NonFungibleESDTv2
• /nfts/TEST-41f2aa-01 should have type NonFungibleESDT and subType NonFungibleESDTv2
• /accounts/erd1e7qgngs0sq2f9fkyqa0ddvy52a66t6yrv9jd09afrn9cqm0lc4cquhm7ug/nfts should return also NFTs of subType NonFungibleESDTv2
• /accounts/erd1e7qgngs0sq2f9fkyqa0ddvy52a66t6yrv9jd09afrn9cqm0lc4cquhm7ug/nfts/TEST-41f2aa-01 should return the NFT of type NonFungibleESDTv2