update .gitignore

add uml diagram to all java solutions

add class diagram to problem markdown file

update uml to uml-diagrams

add uml class diagram for lld problems

update snake and ladder game lld code java

update library management system lld java code

update chess game lld java

update pub sub system java lld code

update tictactoe lld code java

update method names in atm lld java

update valid card method in bankservice atm lld

remmove unused classes from ATM lld java

update atm lld java with state and cor patterns

remove unused methods