Remove virtual and pimpl from single node

Summary:
This diff removes: `SingleNodeRecoveryTransactions`, `TypemapPack`
It also removes virtual and/or pimpl from: `SingleNodeCounters`,
`StorageGcSingleNode`, `SingleNodeConcurrentIdMapper`,
accessors (revert D1510), transaction engine, `GraphDbAccessor`, `GraphDb`

Reviewers: msantl, teon.banek

Reviewed By: msantl, teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1639

tests/unit/interpreter.cpp

@@ -14,7 +14,7 @@
 
 class InterpreterTest : public ::testing::Test {
  protected:
-  database::SingleNode db_;
+  database::GraphDb db_;
   query::Interpreter interpreter_;
 
   auto Interpret(const std::string &query,