Replace olekukonko/tablewriter with cheynewallace/tabby

- Closes #1497
- Closes #1498

This library is simpler and doesn't produce extraneous whitespace around
the output.

A local helper function restores "--" for empty output.

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

internal/app/wwctl/table/table.go

@@ -0,0 +1,24 @@
+package table
+
+import (
+	"io"
+	"text/tabwriter"
+
+	"github.com/cheynewallace/tabby"
+)
+
+func Prep(parts []string) []interface{} {
+	args := make([]interface{}, len(parts))
+	for i, v := range parts {
+		if v == "" {
+			args[i] = "--"
+		} else {
+			args[i] = v
+		}
+	}
+	return args
+}
+
+func New(writer io.Writer) *tabby.Tabby {
+	return tabby.NewCustom(tabwriter.NewWriter(writer, 0, 0, 2, ' ', 0))
+}