Add command aliases for frequently used operations

[Kavirubc]

Problem

Users have to type out full command names which can be verbose for frequently used operations.

Proposed Solution

Add command aliases to make CLI usage faster:

# Instead of:
event-integrator-cli list-events --format json

# Allow:
ei ls -f json

# Common aliases:
- ls → list-events
- rm → remove-event
- up → update-config
- st → status

Benefits

• Faster typing for power users
• More intuitive for users familiar with Unix commands
• Maintains backward compatibility (full names still work)
• Common pattern in modern CLI tools

Implementation

Use Cobra's command aliases feature to support both full and short forms.