Add module based host-tools snapshot

Add new module:
host_snapshot {
    name: "host-snapshot"
    deps: [
      (list of host tools)
    ],
    ...
}

Package host tools using android.PackagingBase to capture host tools and transitive packaging data.
Add JSON meta data to snapshot that allows snapshot to be installed via development/vendor_snapshot/update.py

Add support to generate a fake host snapshot of all host modules that is used to detect required
modules via development/vendor_snapshot/update.py.

Bug: 192556798
Bug: 194799048
Bug: 192896149
Test: m HOST_FAKE_SNAPSHOT_ENABLE=true host-fake-snapshot dist -- check snapshot exists in dist

Change-Id: I849c4db801cd858408f6fe6a3ce69262a23a5be9

snapshot/util.go

@@ -34,3 +34,22 @@ func CopyFileRule(pctx android.PackageContext, ctx android.SingletonContext, pat
 	})
 	return outPath
 }
+
+// zip snapshot
+func zipSnapshot(ctx android.SingletonContext, dir string, baseName string, snapshotOutputs android.Paths) android.OptionalPath {
+	zipPath := android.PathForOutput(
+		ctx, dir, baseName+".zip")
+
+	zipRule := android.NewRuleBuilder(pctx, ctx)
+	rspFile := android.PathForOutput(
+		ctx, dir, baseName+"_list.rsp")
+
+	zipRule.Command().
+		BuiltTool("soong_zip").
+		FlagWithOutput("-o ", zipPath).
+		FlagWithArg("-C ", android.PathForOutput(ctx, dir).String()).
+		FlagWithRspFileInputList("-r ", rspFile, snapshotOutputs)
+
+	zipRule.Build(zipPath.String(), baseName+" snapshot "+zipPath.String())
+	return android.OptionalPathForPath(zipPath)
+}