Refactor ConfiguredAttributeMapper to lib/packages from lib/analysis.

This requires moving the convenience constructor using RuleConfiguredTarget to be owned by RuleConfiguredTarget.

This refactoring is required by later work to allow SplitTransitionProvider to use configurable attributes. This would require packages/Attribute.java -> analysis/ConfiguredAttributeMapper.java, where in general, the 'analysis' package depends on the 'packages' package. This is the easiest way to prevent a circular dependency.

RELNOTES: None.
PiperOrigin-RevId: 171741620
diff --git a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
index e17f74a..55e1f20 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/RuleContext.java
@@ -63,6 +63,7 @@
 import com.google.devtools.build.lib.packages.AttributeMap;
 import com.google.devtools.build.lib.packages.BuildType;
 import com.google.devtools.build.lib.packages.ConfigurationFragmentPolicy;
+import com.google.devtools.build.lib.packages.ConfiguredAttributeMapper;
 import com.google.devtools.build.lib.packages.FileTarget;
 import com.google.devtools.build.lib.packages.FilesetEntry;
 import com.google.devtools.build.lib.packages.ImplicitOutputsFunction;