IBM Spectrum Protect (former name: Tivoli Storage Manager)
provides a single point of control for backup and recovery.
This package contains the client software, that is,
a command line client and linkable libraries.

This commit adds two packages to nixpkgs:
The TSM client software contains a Java GUI
that, naturally, requires Java to be installed.
To keep the closure size low, we provide the packages
`tsm-client` and `tsm-client-withGUI`.
The former comes without the Java GUI.

While the product has been renamed, its old name is still
alive in filenames and as package name used by other distros.

This commit brings a module that installs the
IBM Spectrum Protect (Tivoli Storage Manager)
command-line client together with its
system-wide client system-options file `dsm.sys`.

Based on the programs/tsm-client module,
this commit introduces a systemd service that uses the
tsm-client to create regular backups of the machine.

TSM client