[Fuchsia] Create/Reorganize documentation for Fuchsia

Put Fuchsia specific instructions in //docs/fuchsia
Added instructions for running blink and gpu integration tests.
Added instructions for running tests on remote devices.

Bug: 1174296
Change-Id: I54fabb5b339fe90b3517c6341c62d7269726772f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2673628
Reviewed-by: Sharon Yang <[email protected]>
Reviewed-by: Bob Haarman <[email protected]>
Reviewed-by: Fabrice de Gans-Riberi <[email protected]>
Auto-Submit: Chong Gu <[email protected]>
Commit-Queue: Chong Gu <[email protected]>
Cr-Commit-Position: refs/heads/master@{#854575}
diff --git a/docs/README.md b/docs/README.md
index 0836b43..e6fb53d 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -48,8 +48,8 @@
     (on a Linux host)
 *   [Cast for Android Build Instructions](android_cast_build_instructions.md) -
     Cast for Android (on a Linux host)
-*   [Fuchsia Build Instructions](fuchsia_build_instructions.md) - Fuchsia target
-    (on a Linux host)
+*   [Fuchsia Build Instructions](fuchsia/build_instructions.md) -
+    Fuchsia target (on a Linux host)
 *   [iOS Build Instructions](ios/build_instructions.md) - iOS target (on a MacOS
     host)
 *   [Chrome OS Build Instructions](chromeos_build_instructions.md) - Chrome OS