* Don't purge cards-by-rarity cache between tournaments
* Move DOM and WAR specific checks out of base ExpansionSet class
* Move Battlebond specific methods out of base ExpansionSet class
* Refactor ExpansionSet and subclasses
* Zendikar boosters also only have full-art basic lands
* Fix Eldritch Moon (#8171)
- replacing hard coded strings of set codes with reference to 'mage.sets.<set>.getInstance().getCode()' allows for set class names to no longer show as unreferenced & adds for more consistence between other block units
- various protected variables were able to be changed to private to clean up additional warnings
- some JavaDoc comments were generating warnings due to missing documentation
- removed some unused imports and unused variables
- there were multiple conditional logic checks for 'rarity != Rarity.LAND' within an if block where the outer condition was 'if rarity == Rarity.COMMON' rendering the inner condition always true and thus redundant
- a few ExpansionSet.buildDate parameters wer using octal values (eg. '03' instead of '3') which triggered some warnings
- added a booster generation test for WarOfTheSparks to make sure every booster contains a planeswalker
- added a booster generation test for ModernHorizons to make sure every booster contains a snow land
- booster generation test for Battlbond set referenced the Coldsnap set class instead of Battlebond
replaced by the common taplands, that do NOT appear in the booster.
Previously the taplands had the same chance to be generated as the
basics, now they are generated with the proper odds.
