tidy up, split code out of commands into git package

src/main/java/command/CommandCreate.java

src/main/java/command/CommandInit.java

src/main/java/git/IssueReader.java

src/main/java/git/IssueRepo.java

src/main/java/git/IssueTreeBuilder.java

src/main/java/git/ObjectInserter.java

src/main/java/issueData/IssueRepository.java