[infra] Add tools, move infra/infra.

The motivation is to include the tools repo in the manifest because
many users of this manifest use that code as well.

Also move infra/infra from fuchsia-infra/go/src to just
fuchsia-infra/infra.
Apparently putting go source code into a directory structure that
matches the go package structure is no longer needed now that we use
go modules, which we do for both tools and infra/infra.

Change-Id: I5713276e9b08b041207d64016e7d9a88658c328e
diff --git a/infra b/infra
index 8de79ee..9b4b16d 100644
--- a/infra
+++ b/infra
@@ -16,7 +16,7 @@
              remote="https://fuchsia.googlesource.com/infra"
              gerrithost="https://fuchsia-review.googlesource.com"/>
     <project name="fuchsia-infra/infra"
-             path="fuchsia-infra/go/src/fuchsia.googlesource.com/infra/infra"
+             path="fuchsia-infra/infra"
              remote="https://fuchsia.googlesource.com/infra/infra"
              gerrithost="https://fuchsia-review.googlesource.com"/>
     <project name="fuchsia-infra/config"
@@ -32,6 +32,10 @@
              path="fuchsia-infra/recipes"
              remote="https://fuchsia.googlesource.com/infra/recipes"
              gerrithost="https://fuchsia-review.googlesource.com"/>
+    <project name="tools"
+             path="tools"
+             remote="https://fuchsia.googlesource.com/tools"
+             gerrithost="https://fuchsia-review.googlesource.com"/>
   </projects>
   <hooks>
     <hook name="update-prebuilt"