Add a "dump" output option to git-list

It prints a list of all repos URL and is supposed to be consumed by `git get --dump` option.

pkg/print/dump.go

@@ -0,0 +1,37 @@
+package print
+
+import (
+	"git-get/pkg/git"
+	"strings"
+)
+
+type DumpPrinter struct{}
+
+// Print generates a list of repos URLs. Each line contains a URL and, if applicable, a currently checked out branch name.
+// It's a way to dump all repositories managed by git-get and is supposed to be consumed by `git get --dump`.
+func (p *DumpPrinter) Print(_ string, repos []*git.Repo) string {
+	var str strings.Builder
+
+	for i, repo := range repos {
+		remotes, err := repo.Remotes()
+		if err != nil || len(remotes) == 0 {
+			continue
+		}
+
+		// TODO: Needs work. Right now we're just assuming the first remote is the origin one and the one from which the current branch is checked out.
+		url := remotes[0].Config().URLs[0]
+		current := repo.Status.CurrentBranch
+
+		str.WriteString(url)
+
+		if current != git.StatusDetached && current != git.StatusUnknown {
+			str.WriteString(" " + current)
+		}
+
+		if i < len(repos)-1 {
+			str.WriteString("\n")
+		}
+	}
+
+	return str.String()
+}