feature/featuretags: move list of omit-able features to a Go package

Updates #12614

Change-Id: I4012c33095c6a7ccf80ad36dbab5cedbae5b3d47
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

feature/featuretags/featuretags.go

@@ -0,0 +1,27 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+// The featuretags package is a registry of all the ts_omit-able build tags.
+package featuretags
+
+var Features = map[string]string{
+	"aws":              "AWS integration",
+	"bird":             "Bird BGP integration",
+	"capture":          "Packet capture",
+	"cli":              "embed the CLI into the tailscaled binary",
+	"completion":       "CLI shell completion",
+	"debugeventbus":    "eventbus debug support",
+	"desktop_sessions": "Desktop sessions support",
+	"drive":            "Tailscale Drive (file server) support",
+	"kube":             "Kubernetes integration",
+	"relayserver":      "Relay server",
+	"ssh":              "Tailscale SSH support",
+	"syspolicy":        "System policy configuration (MDM) support",
+	"systray":          "Linux system tray",
+	"taildrop":         "Taildrop (file sending) support",
+	"tap":              "Experimental Layer 2 (ethernet) support",
+	"tka":              "Tailnet Lock (TKA) support",
+	"tpm":              "TPM support",
+	"wakeonlan":        "Wake-on-LAN support",
+	"webclient":        "Web client support",
+}