Gas Optimizations

[code423n4]

1. Can use stricter visibility: public constant variables can be set as private as code is open source and they are also in the docs
https://github.com/code-423n4/2022-03-paladin/blob/main/contracts/HolyPaladinToken.sol#L17-L39

2. Slight change in protocol design can save lots of gas paid for by users: function _updateDropPerSecond() is called with almost every interaction with the contract. This function adds minimum 2k gas to 6 different functions called by users and also on every transfer of tokens. Consider using a function that updates drop per second separately and allow anyone to call it, reward those who call it with a successful update with a small (slightly more than the price of gas) incentive, maybe in the native token. This will utilize MEV to the protocols advantage.
https://github.com/code-423n4/2022-03-paladin/blob/main/contracts/HolyPaladinToken.sol#L713-L742

[Kogaroshi]

QA & gas optimizations changes are done in the PR: PaladinFinance/Paladin-Tokenomics#6
(some changes/tips were implemented, others are noted but won't be applied)