Release FeralfileExhibitionV4 for Feral File 2.0

During the re-design of Feral File 2.0, the contract is also re-designed accordingly to support new naming rules,
and a transparent and flexible sale method in Feral File.

The new FeralfileExhibitionV4 contract is a token contract including sale functions. All the sales would
settled over blockchain directly. This contract provides a flexible way for Feral File to propose the sale data
for users to submit transactions by themselves.

The significant changes compare to the previous FeralfileExhibitionV3 contract:

• buyArtworks - function for settle purchasing transaction from blockchain
  • Support meta transaction
  • Private vault integration, allow credit card users to delegate payments to Feral File
• Re-design the token structure by
  • Series
  • Artwork

v3.2.0

This release is aim to support operator filter registry from opensea

• Add UpdateableOperatorFilterer which enable us to change OperatorFiltererRegistry in the future
• Set to use opensea registry be default