fix: UI for filtering config options

Also added vim-like movement (hjkl, g, shift+g)
  h -> left
  j -> down
  k -> up
  l -> right
  g -> Go to first config
  shift+g -> Go to last config

config_test.go

@@ -0,0 +1,23 @@
+package main
+
+import "testing"
+
+func TestFilterConfigs(t *testing.T) {
+	cfgs := filter(Configs, "Preset", "Constant Rate Factor (CRF)")
+
+	for _, cfg := range cfgs {
+		if cfg.Name == "Preset" {
+			t.Fatalf("Failed to filter out config \"Preset\"")
+		} else if cfg.Name == "Constant Rate Factor (CRF)" {
+			t.Fatalf("Failed to filter out config \"Constant Rate Factor (CRF)\"")
+		}
+	}
+}
+
+func TestGetVisibleConfigs(t *testing.T) {
+	cfgs := getVisibleConfigs(Configs)
+
+	if len(cfgs) == len(Configs) {
+		t.Fatalf("Failed to get the correct visible configs. Expected VisibleConfigs len: %v. Got %v", 4, len(cfgs))
+	}
+}