feat: Connection handling with Gazer

[drstrangelooker]

Added cat, rm, test, and import commands.

$ exe/gzr help connection
Commands:
  gzr connection cat CONNECTION_NAME   # Output the JSON representation of a connection to the screen or a file
  gzr connection dialects              # List all available dialects
  gzr connection help [COMMAND]        # Describe subcommands or one specific subcommand
  gzr connection import FILE           # Import a connection from a file
  gzr connection ls                    # List all available connections
  gzr connection rm CONNECTION_NAME    # Delete a connection
  gzr connection test CONNECTION_NAME  # Test the given connection

[github-actions]

Ruby-CI Tests

    4 files      4 suites   1m 22s ⏱️
136 tests 136 ✔️ 0 💤 0 ❌
544 runs  544 ✔️ 0 💤 0 ❌

Results for commit 9773010.

[jkaster]

LGTM