fix: add helpful output to the help command

[baruchiro]

• make functions private
• add helpful examples for -h/--help/help

Close #43

❯ go run .
2ms Secrets Detection: A tool to detect secrets in public websites and communication services.

Usage:
  2ms [command]

Plugins
  confluence  Scan Confluence server
  discord     Scan Discord server
  repository  Scan local repository

Additional Commands:
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command

Flags:
  -h, --help               help for 2ms
      --log-level string   log level (trace, debug, info, warn, error, fatal) (default "info")
      --tags strings       select rules to be applied (default [all])
  -v, --version            version for 2ms

Use "2ms [command] --help" for more information about a command.

❯ go run . help confluence
Scan Confluence server for sensitive information

Usage:
  2ms confluence --url URL [flags]

Flags:
  -h, --help                 help for confluence
      --history              Scan pages history
      --spaces stringArray   Confluence spaces: The names or IDs of the spaces to scan
      --token string         The Confluence API token for authentication
      --url string           Confluence server URL (example: https://company.atlassian.net/wiki) [required]
      --username string      Confluence user name or email for authentication

Global Flags:
      --log-level string   log level (trace, debug, info, warn, error, fatal) (default "info")
      --tags strings       select rules to be applied (default [all])

❯ go run . help discord
Scan Discord server for sensitive information.

Usage:
  2ms discord --token TOKEN --server SERVER [flags]

Flags:
      --channel stringArray   Discord channels IDs to scan. If not provided, all channels will be scanned
      --duration duration     The time interval to scan from the current time. For example, 24h for 24 hours or 7d for 7 days. (default 336h0m0s)
  -h, --help                  help for discord
      --messages-count int    The number of messages to scan. If not provided, all messages will be scanned until the fromDate flag value.
      --server stringArray    Discord servers IDs to scan [required]
      --token string          Discord token [required]

Global Flags:
      --log-level string   log level (trace, debug, info, warn, error, fatal) (default "info")
      --tags strings       select rules to be applied (default [all])

❯ go run . help repository
Scan local repository for sensitive information

Usage:
  2ms repository --path PATH [flags]

Flags:
  -h, --help          help for repository
      --path string   Local repository path [required]

Global Flags:
      --log-level string   log level (trace, debug, info, warn, error, fatal) (default "info")
      --tags strings       select rules to be applied (default [all])

[baruchiro]

Waits for #61

[github-actions]

KICS version: v1.7.0

Category Results HIGH 0 MEDIUM 0 LOW 1 INFO 0 TRACE 0 TOTAL 1	Metric Values Files scanned 1 Files parsed 1 Files failed to scan 0 Total executed queries 49 Queries failed to execute 0 Execution time 2