determine automatically if artifact is a snapshot or not

Currently, the artifact plugin defines a taglibary with
tags to install/deploy "release" artifacts and other tags to install/deploy snapshot artifacts.

This distinction, although comprehensible from a technical point of view, should be hidden away from the clients of the artifact plugin.
From the users point of view there is just an artifact which should be installed or deployed, be it a snapshot or not.
To differ between them introduces unnecessary complexity and also adds possibilities for usage errors (ie, trying to install snapshots, to install-snapshot release versions and so on).

IMHO, there should be only two tags, one to deploy and one to install an artifact. A possible implementation just needs to check the filename for SNAPSHOT_SIGNIFIER. If it is part of the artifacts file name, treat it as a snapshot, otherwise not.

To avoid breaking anything, the proposed tags can be added in addition to the existing tags. After a transition period the current tags should be removed.