FIR IDE: rewrite low level API

- Cache ModuleResolveState for module till the world changes
- Resolve every file under a lock
- All creation of raw fir files and resolve of them happens in FirFileBuilder
- Lazy resolve of fir elements happens in FirElementBuilder

Caching works like the following:
- FirModuleResolveState holds PsiToFirCache & DiagnosticsCollector & FileCacheForModuleProvider
- FileCacheForModuleProvider holds a mapping from ModuleInfo to ModuleFileCache
- ModuleFileCache caches
    - KtFile -> FirFile mapping
    - ClassId -> FirClassLikeDeclaration, CallableId -> FirCallableSymbol
        which used in corresponding FirProvider
    - mapping from declaration to it's file
        which used in corresponding FirProvider
    - locks for fir file resolving
- PsiToFirCache provides mapping from KtElement to  FirElement
- DiagnosticsCollector collects diagnostics for file and caches them

idea/idea-analysis/src/org/jetbrains/kotlin/idea/stubindex/KotlinFullClassNameIndex.java

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
  */
 
 package org.jetbrains.kotlin.idea.stubindex;
@@ -28,7 +17,7 @@ import org.jetbrains.kotlin.psi.KtClassOrObject;
 import java.util.Collection;
 
 public class KotlinFullClassNameIndex extends StringStubIndexExtension<KtClassOrObject> {
-    private static final StubIndexKey<String, KtClassOrObject> KEY = KotlinIndexUtil.createIndexKey(KotlinFullClassNameIndex.class);
+    public static final StubIndexKey<String, KtClassOrObject> KEY = KotlinIndexUtil.createIndexKey(KotlinFullClassNameIndex.class);
 
     private static final KotlinFullClassNameIndex ourInstance = new KotlinFullClassNameIndex();