MESH-2110/Add storage for tracking an NFT owner

[HenriqueNogara]

Adds a storage for tracking the owner of an NFT.

changelog

data migration

• Initializes the new storage with data that already lives on chain.

[codecov[bot]]

Codecov Report

Merging #1546 (d53f0d2) into develop (d4a4e25) will decrease coverage by 0.04%. The diff coverage is 16.66%.

@@             Coverage Diff             @@
##           develop    #1546      +/-   ##
===========================================
- Coverage    58.53%   58.50%   -0.04%     
===========================================
  Files          142      142              
  Lines        31996    32008      +12     
===========================================
- Hits         18730    18727       -3     
- Misses       13266    13281      +15     

Files	Coverage Δ
pallets/weights/src/pallet_nft.rs	0.00% <0.00%> (ø)
pallets/nft/src/lib.rs	56.27% <21.42%> (-0.84%)	:arrow_down:

... and 4 files with indirect coverage changes