Add advanced storage/partitioning option snippets (logvol, raid, volgroup, reqpart)

[sfloess]

Part of #15: Include all option snippets as found in the kickstart guide.

Scope

Add option snippets for advanced storage and partitioning kickstart commands that are currently missing:

• logvol - Create logical volumes for LVM (logvol mntpoint --vgname=name --name=name [options])
• raid - Assemble a software RAID device (raid mntpoint --level= --device= partitions)
• volgroup - Create an LVM volume group (volgroup name partition [options])
• reqpart - Automatically create partitions required by the hardware platform (e.g., UEFI ESP, PReP boot)

Reference

RHEL 7 Kickstart Syntax Reference - Section 27.3

Acceptance Criteria

• Each command has a corresponding snippet file under snippets/options/
• Snippets follow the existing pattern/style used by other option snippets in the repo
• Key options for each command are parameterized via cobbler variables