fix: receive and save NFTs sent directly to the extensions

[fforbeck]

Proposed Changes

• The NFTAdapter was created to collect ERC721 and send them to the ERC721 extension, but the extension contains the onERC721Received function which is called when the token is transferred in the NFT contract, this change fixes the onERC721Received in NFTExtension to save the NFT in the internal storage so the tokens can be sent directly to the extension.
• Deleted the NFTAdapter and fixed the tests.

[codecov]

Codecov Report

Merging #440 (02347c2) into master (7eb07c9) will increase coverage by 0.10%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #440      +/-   ##
==========================================
+ Coverage   80.85%   80.96%   +0.10%     
==========================================
  Files          47       46       -1     
  Lines        1656     1655       -1     
  Branches      390      390              
==========================================
+ Hits         1339     1340       +1     
+ Misses        317      315       -2     

Impacted Files	Coverage Δ
contracts/extensions/nft/NFT.sol	83.01% <100.00%> (+0.66%)	⬆️
...racts/extensions/erc1155/ERC1155TokenExtension.sol	77.02% <0.00%> (+2.70%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 7eb07c9...02347c2. Read the comment docs.