databaseInitCluster: use overlayDatabaseMode from config

This commit changes databaseInitCluster() to use overlayDatabaseMode
from AugmentationProperties instead of the overlayDatabaseMode
parameter. There is no behavior change because both overlayDatabaseMode
values are computed the same way.

The commit then cleans up the overlayDatabaseMode parameter and the code
paths that feed into it.

src/codeql.ts

@@ -87,7 +87,6 @@ export interface CodeQL {
     sourceRoot: string,
     processName: string | undefined,
     qlconfigFile: string | undefined,
-    overlayDatabaseMode: OverlayDatabaseMode,
     logger: Logger,
   ): Promise<void>;
   /**
@@ -564,7 +563,6 @@ export async function getCodeQLForCmd(
       sourceRoot: string,
       processName: string | undefined,
       qlconfigFile: string | undefined,
-      overlayDatabaseMode: OverlayDatabaseMode,
       logger: Logger,
     ) {
       const extraArgs = config.languages.map(
@@ -602,6 +600,8 @@ export async function getCodeQLForCmd(
         ? "--force-overwrite"
         : "--overwrite";
 
+      const overlayDatabaseMode =
+        config.augmentationProperties.overlayDatabaseMode;
       if (overlayDatabaseMode === OverlayDatabaseMode.Overlay) {
         const overlayChangesFile = await writeOverlayChangesFile(
           config,