Remove unused mk_payload

It was used to build a payload composite disk for microdroid and ARCVM.
But since ARCVM is no longer use block APEXes and microdroid's payload
disk is created by virtmgr now.

Bug: 269409253
Test: m
Change-Id: Ibe305fe9f84679c0042b21bc4bddecc3047e78d3
diff --git a/microdroid/payload/Android.bp b/microdroid/payload/Android.bp
index c8d1044..4814a64 100644
--- a/microdroid/payload/Android.bp
+++ b/microdroid/payload/Android.bp
@@ -46,28 +46,3 @@
         type: "lite",
     },
 }
-
-cc_binary_host {
-    name: "mk_payload",
-    srcs: [
-        "mk_payload.cc",
-    ],
-    static_libs: [
-        "lib_microdroid_metadata_proto",
-        "libbase",
-        "libcdisk_spec",
-        "libcuttlefish_fs",
-        "libcuttlefish_host_config",
-        "libcuttlefish_utils",
-        "libext2_uuid",
-        "libimage_aggregator",
-        "libjsoncpp",
-        "liblog",
-        "libprotobuf-cpp-full",
-        "libprotobuf-cpp-lite",
-        "libsparse",
-        "libxml2",
-        "libz",
-    ],
-    static_executable: true,
-}
diff --git a/microdroid/payload/README.md b/microdroid/payload/README.md
index c2f624a..b1eb63f 100644
--- a/microdroid/payload/README.md
+++ b/microdroid/payload/README.md
@@ -38,34 +38,3 @@
 Each payload partition presents APEX or APK passed from the host.
 
 The size of a payload partition must be a multiple of 4096 bytes.
-
-# `mk_payload`
-
-`mk_payload` is a small utility to create a payload disk image. It is used by ARCVM.
-
-```
-$ cat payload_config.json
-{
-  "apexes": [
-    {
-      "name": "com.my.hello",
-      "path": "hello.apex",
-    }
-  ],
-  "apk": {
-    "name": "com.my.world",
-    "path": "/path/to/world.apk",
-    "idsigPath": "/path/to/world.apk.idsig",
-  }
-}
-$ m mk_payload
-$ mk_payload payload_config.json payload.img
-$ ls
-payload.img
-payload-footer.img
-payload-header.img
-payload-metadata.img
-payload-filler-0.img
-payload-filler-1.img
-...
-```