Add objects for NFTokenPages

[nkramer44]

Fixes #430 and #431

[codecov]

Codecov Report

Merging #432 (185a59d) into main (1d34a3e) will increase coverage by 0.24%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main     #432      +/-   ##
============================================
+ Coverage     90.30%   90.54%   +0.24%     
- Complexity     1432     1452      +20     
============================================
  Files           277      281       +4     
  Lines          4125     4147      +22     
  Branches        339      339              
============================================
+ Hits           3725     3755      +30     
+ Misses          279      271       -8     
  Partials        121      121              

Impacted Files	Coverage Δ
...pl/xrpl4j/model/client/accounts/NfTokenObject.java	100.00% <ø> (ø)
...rg/xrpl/xrpl4j/model/transactions/NfTokenMint.java	100.00% <ø> (ø)
...rpl4j/model/client/accounts/AccountNftsResult.java	87.50% <100.00%> (+70.83%)	⬆️
...l/client/accounts/AccountObjectsRequestParams.java	100.00% <100.00%> (+22.22%)	⬆️
...java/org/xrpl/xrpl4j/model/flags/NfTokenFlags.java	100.00% <100.00%> (ø)
...odel/jackson/modules/AffectedNodeDeserializer.java	100.00% <100.00%> (ø)
...j/model/jackson/modules/TransferFeeSerializer.java	100.00% <100.00%> (ø)
...ava/org/xrpl/xrpl4j/model/ledger/LedgerObject.java	84.00% <100.00%> (+0.66%)	⬆️
...ain/java/org/xrpl/xrpl4j/model/ledger/NfToken.java	100.00% <100.00%> (ø)
...rg/xrpl/xrpl4j/model/ledger/NfTokenPageObject.java	100.00% <100.00%> (ø)
... and 2 more