Add the possibility to handle a list of all groups, artifacts and versions in a repo

[phax]

• The "Top ToC" does not work, because it only handles groups and artifacts
• The "per artifact" version handling is good, but does not scale with many artifacts as it would require 1 GET per artifact

Suggestion: provide one large CSV file, with the following columns:

• Group ID (string)
• Artifact ID (string)
• Version (string)
• Deprecated? (boolean)
• Display Name (string) - to be added in IValidationExecutorSetStatus (see Add Display Name to IValidationExecutorSetStatus #30)

• CSV is preferred to e.g. SQLite, as the data is more easily processable and does not require a proprietary technology
• Usage of RDF would be nice, but doesn't really scale too well

The "fulltoc" needs modification, on the following activities:

• Add a new version - special handling for SNAPSHOTs
• Delete an existing version (if the repo allows it)
• If the deprecation status of a version changes
• If the display name of a version changes

Allow the "fulltoc" to be serialized in different forms - start with CSV and comma as a separator