UC39

This PR contains UC39, which allows the admin and tester to view previous transaction logs, either in list or graph form

To test in iTrust:

1. Log in as admin (or tester)
2. Click on Other menu tab, and click on View Transaction Logs
3. Try testing looking up transaction logs based on different parameters, both in list view and graph view

To run the tests, do the following:

1. First, run mvn install -DskipTests to build and deploy the website (this will ensure that the selenium tests work as expected)
2. Run mvn test -Dtest=LogTransactionTest and mvn test -Dtest=TransactionWithRoleBeanTest to run the unit tests
3. Run mvn test -Dtest=ViewTransactionLogsTest to run the selenium tests