Add commands to help add tools to the configuration

[wagoodman]

Adds the following commands:

$ binny add --help 

...
Available Commands:
  github-release Add a new tool configuration that sources binaries from GitHub releases
  go-install     Add a new tool configuration from 'go install ...' invocations

Github release help:

Add a new tool configuration that sources binaries from GitHub releases

Usage:
  binny add github-release OWNER/REPO@VERSION [flags]

Flags:
      --constraint string     Version constraint (e.g. '<2.0' or '>=1.0.0')
  -h, --help                  help for github-release
      --verify-sha256         Verifying the sha256 digest of already installed tools (by default xxh64 is used)
  -f, --version-from string   The method to use to resolve the version (available: [github-release goproxy git])

Go install help:

Add a new tool configuration from 'go install ...' invocations

Usage:
  binny add go-install NAME@VERSION --module GOMODULE [--entrypoint PATH] [--ldflags FLAGS] [flags]

Flags:
      --constraint string     Version constraint (e.g. '<2.0' or '>=1.0.0')
  -e, --entrypoint string     Entrypoint within the go module (e.g. cmd/syft)
  -h, --help                  help for go-install
  -l, --ld-flags string       LD flags to pass to the go install command (e.g. -ldflags "-X main.version=1.0.0")
  -m, --module string         Go module (e.g. github.com/anchore/syft)
      --verify-sha256         Verifying the sha256 digest of already installed tools (by default xxh64 is used)
  -f, --version-from string   The method to use to resolve the version (available: [github-release goproxy git])