refactor mf-check to include size and checksum in the result csv.

docs/unimelb-mf-check.md

src/main/java/unimelb/mf/client/sync/MFSyncApp.java

src/main/java/unimelb/mf/client/sync/check/AssetItem.java

src/main/java/unimelb/mf/client/sync/check/CheckResult.java

src/main/java/unimelb/mf/client/sync/check/ChecksumType.java

...ava/unimelb/mf/client/sync/check/DefaultCheckHandler.java

src/main/java/unimelb/mf/client/sync/check/FileItem.java

src/main/java/unimelb/mf/client/sync/check/HasChecksum.java

src/main/java/unimelb/mf/client/sync/check/HasContent.java

src/main/java/unimelb/mf/client/sync/check/Item.java

src/main/java/unimelb/mf/client/sync/cli/MFCheck.java

...imelb/mf/client/sync/task/AssetNamespaceDownloadTask.java

...n/java/unimelb/mf/client/sync/task/AssetSetCheckTask.java

...in/java/unimelb/mf/client/sync/task/FileSetCheckTask.java

src/main/java/unimelb/utils/PathUtils.java