MVDFunctionalityProposalManager retireAll method stack too deep.

[PaoloRollo]

Currently the retireAll method inside the MVDFunctionalityProposalContract blocks its compilation by raising a stack too deep error.

This is the current method implementation:

    /** @dev Allows the sender to retire all the tokens used for voting in this proposal.
      * @param proposalId proposal identifier.
     */
    function retireAll(uint256 proposalId) public override duringSurvey(proposalId) {
        require(_proposals[proposalId].getItemProposalWeightFunctionalityAddress != address(0), "");
        IGetItemProposalWeightFunctionality functionality = IGetItemProposalWeightFunctionality(_proposals[proposalId].getItemProposalWeightFunctionalityAddress);
        uint256 total = 0;
        address[] memory collections = _userCollectionAddresses[proposalId][msg.sender];
        for (uint j = 0; j < collections.length; j++) {
            uint256[] memory amounts = new uint256[](_userObjectIds[proposalId][msg.sender][collections[j]].length);
            for (uint256 i = 0; i < _userObjectIds[proposalId][msg.sender][collections[j]].length; i++) {
                require(_accept[proposalId][msg.sender][_userObjectIds[proposalId][msg.sender][collections[j]][i]] + _refuse[proposalId][msg.sender][_userObjectIds[proposalId][msg.sender][collections[j]][i]] > 0, "");
            }
            for (uint256 i = 0; i < _userObjectIds[proposalId][msg.sender][collections[j]].length; i++) {
                uint256 tokenWeight = functionality.getItemProposalWeight(collections[j], _userObjectIds[proposalId][msg.sender][collections[j]][i]);
                if (tokenWeight > 0) {
                    uint256 acpt = _accept[proposalId][msg.sender][_userObjectIds[proposalId][msg.sender][collections[j]][i]];
                    uint256 rfs = _refuse[proposalId][msg.sender][_userObjectIds[proposalId][msg.sender][collections[j]][i]];
                    uint256 wAcpt = acpt / tokenWeight;
                    uint256 wRfs = rfs / tokenWeight;
                    amounts[i] = wAcpt + wRfs;
                    _accept[proposalId][msg.sender][_userObjectIds[proposalId][msg.sender][collections[j]][i]] = 0;
                    _refuse[proposalId][msg.sender][_userObjectIds[proposalId][msg.sender][collections[j]][i]] = 0;
                    _totalAccept[proposalId] -= acpt;
                    _totalRefuse[proposalId] -= rfs;
                    total += (acpt + rfs);
                } else {
                    amounts[i] = 0;
                }
            }
            IEthItemCollection(collections[j]).safeBatchTransferFrom(address(this), msg.sender, amounts, _userObjectIds[proposalId][msg.sender][collections[j]], "");
        }
        emit RetireAll(msg.sender, proposalId, total);
    }

It raises a stack too deep because there are too many nested mappings; a solution could be splitting the function into two retireAllAccept and retireAllRefuse.