Renames diagnostic query files and tests

This commit renames the files relating to the diagnostic query that produces information on the number of files extracted. The files have been renamed from "SuccessfullExtractedFiles.*" to "ExtractedFiles.*". All related tests and test files have been renamed too.

The `@tags` and `@id` attributes of the queries have been left untouched, consistent with the `@tags` and `@id` for similar queries in other languages.

Author: sidshank

javascript/ql/src/Diagnostics/SuccessfullyExtractedFiles.ql renamed to javascript/ql/src/Diagnostics/ExtractedFiles.ql

@@ -0,0 +1 @@
+Diagnostics/ExtractedFiles.ql

javascript/ql/test/query-tests/Diagnostics/SuccessfullyExtractedFiles.expected renamed to javascript/ql/test/query-tests/Diagnostics/ExtractedFiles.expected

@@ -0,0 +1 @@
+Diagnostics/ExtractedFiles.ql