We want to export some of our CLI code to re-use in other projects. But
in Golang you cannot import code from a `main` package.
So we need to move the actual code into its own package and only have
the `func main()` in the `main` package.
This commit adds three optional command line flags to the
encryptdebugpackage: --peers, --onchain and --channels.
Each of them adds the output of extra commands to the encrypted debug
package.
