Add Skills covering the LD CLI

[kallevmercury]

Summary

Hello! I have been testing out the LD skills with the MCP and they work great. I'd also like to do the same with the CLI and have similar coverage of the CLI skills: https://github.com/launchdarkly/ldcli.

Problem Statement

No "official" ldcli Agent skills are published by LaunchDarkly.

Proposed Solution

Add ldcli skills to the repository.

Alternatives Considered

Writing my own skills for the ldcli. This is my current workaround.