Include microdroid files to virt apex

All files to run microdroid is now included to the com.android.virt
APEX:

- super image
- boot images
- vbmeta images
- bootloader
- uboot_env image
- cdisk json config

Also the documentation README.md and microdroid host tests are updated
too.

Bug: 184803590
Test: follow instructions on README.md
Test: atest MicrodroidHostTestCases
Change-Id: I71f0e32ca774b351d9f49af2754f0a1c786c2400
diff --git a/apex/Android.bp b/apex/Android.bp
index 5357566..bc9e084 100644
--- a/apex/Android.bp
+++ b/apex/Android.bp
@@ -20,12 +20,26 @@
                 "authfs", // TODO(victorhsieh): move to microdroid once we can run the test in VM.
                 "crosvm",
             ],
+            filesystems: [
+                "microdroid_super",
+                "microdroid_boot-5.10",
+                "microdroid_vendor_boot-5.10",
+                "microdroid_vbmeta",
+                "microdroid_vbmeta_system",
+            ],
         },
         x86_64: {
             binaries: [
                 "authfs", // TODO(victorhsieh): move to microdroid once we can run the test in VM.
                 "crosvm",
             ],
+            filesystems: [
+                "microdroid_super",
+                "microdroid_boot-5.10",
+                "microdroid_vendor_boot-5.10",
+                "microdroid_vbmeta",
+                "microdroid_vbmeta_system",
+            ],
         },
     },
     binaries: [
@@ -34,8 +48,12 @@
         "virtmanager",
         "vm",
     ],
-    filesystems: ["microdroid"],
-    prebuilts: ["com.android.virt.init.rc"],
+    prebuilts: [
+        "com.android.virt.init.rc",
+        "microdroid_cdisk.json",
+        "microdroid_uboot_env",
+        "microdroid_bootloader",
+    ],
     file_contexts: ":com.android.virt-file_contexts",
 }