WiX: remove the ICU projects

This removes the ICU packaging support.  Now that we can build our own
ICU, we can statically link against ICU as it is only used for
Foundation.  This removes the need for the additional packaging.  Clean
up the packaging rules and remove it from the default set.

Author: compnerd

platforms/Windows/icu-amd64.wxs

@@ -12,7 +12,7 @@
     <ProductVersion>$(ProductVersion)</ProductVersion>
 
     <!-- The list must be %3B (;) separated so that it is passed along properly as `;` normally delimit options -->
-    <RequiredChain Condition=" '$(RequiredChain)' == '' ">icu.msi%3Bruntime.msi%3Btoolchain.msi%3Bdevtools.msi%3Bsdk.msi</RequiredChain>
+    <RequiredChain Condition=" '$(RequiredChain)' == '' ">runtime.msi%3Btoolchain.msi%3Bdevtools.msi%3Bsdk.msi</RequiredChain>
     <RequiredChain>$(RequiredChain)</RequiredChain>
 
     <OptionalChain>$(OptionalChain)</OptionalChain>