HIP - 367 : Remove limit on the number of tokens that can be associated to an account

[anighanta]

• Remove the restriction on the number of tokens that can be associated to the account that is dictated by property "tokens.maxPerAccount"
• Use a map valued linkedList <EntityNumPair, MerkleTokenRelStatus> instead of using CopyOfWriteIds array to track the associated token Ids where MerkleTokenRelStatus serves as a doubly linkedList node.
• Track the latest association using a EntityNumPair on MerkleAccount using the new TokenAssociaitonMetadata which will encapsulate numAssociations -> current token association count, numZeroBalances -> zero balanced token associations among the current associations and lastAssociation -> EntityNumPair of last token association.
• MerkleAccount will no longer have 3 children. It will have just 2 from this release on [merkelAccountState and Records]
• Migration from older version states should work with updating the linked list with the appropriate links and setting the latest association of the MerkleAccount along with numAssociaitons and numZeroBalances.
• Association and Dissociation logics should manipulate the linkedList and TokenAssociaitonMetadata as expected
• GetAccountInfo/Balance will have only a limited amount of token association data in them [dictated by "tokens.maxPerAccount"`]
• CryptoDelete no longer skips validating zero token balances on deleted tokens. All associated token balances must be zero and one would have to dissociate/transfer away any token balances to be eligible for deletion.
• TokenBurn, TokenMint and TokenWipe operations should update the treasury's/account's numZeroBalances in their TokenAssociaitonMetadata respectively.
• CryptoTransfer should update the sender's and receiver's numZeroBalances accordingly