Large re-organization to split daggyd away from the core libdaggy.

This paves the way for implementing daggys and other utilities.

Squashed commit of the following:

commit 1f77239ab3c9e44d190eef94531a39501c8c4dfe
Author: Ian Roddis <gitlab@ie2r.com>
Date:   Mon Oct 18 16:25:02 2021 -0300

    Adding README, stdout support for daggyd logging

commit c2c237224e84a3be68aaa597ce98af1365e74a13
Author: Ian Roddis <gitlab@ie2r.com>
Date:   Mon Oct 18 16:10:29 2021 -0300

    removing old daggyd

commit cfea2baf61ca10c535801c5a391d2d525a1a2d04
Author: Ian Roddis <gitlab@ie2r.com>
Date:   Mon Oct 18 16:10:09 2021 -0300

    Moving tests into their sub-project folders

commit e41ca42069bea1db16dd76b6684a3f692fef6b15
Author: Ian Roddis <gitlab@ie2r.com>
Date:   Mon Oct 18 15:57:40 2021 -0300

    Splitting out daggyd from libdaggy

commit be97b146c1d2446f5c03cb78707e921f18c60bd8
Author: Ian Roddis <gitlab@ie2r.com>
Date:   Mon Oct 18 15:56:55 2021 -0300

    Splitting out daggyd from libdaggy

commit cb61e140e9d6d8832d61fb7037fd4c0ff6edad00
Author: Ian Roddis <gitlab@ie2r.com>
Date:   Mon Oct 18 15:49:47 2021 -0300

    moving daggy to libdaggy

daggyd/libdaggyd/include/daggyd/Server.hpp

@@ -0,0 +1,67 @@
+#pragma once
+
+#include <pistache/description.h>
+#include <pistache/endpoint.h>
+#include <pistache/http.h>
+
+#include <daggy/DAGRunner.hpp>
+#include <daggy/ThreadPool.hpp>
+#include <daggy/executors/task/TaskExecutor.hpp>
+#include <daggy/loggers/dag_run/DAGRunLogger.hpp>
+#include <filesystem>
+
+#define DAGGY_REST_HANDLER(func)                    \
+  void func(const Pistache::Rest::Request &request, \
+            Pistache::Http::ResponseWriter response);
+
+namespace fs = std::filesystem;
+
+namespace daggy {
+  class Server
+  {
+  public:
+    Server(const Pistache::Address &listenSpec,
+           loggers::dag_run::DAGRunLogger &logger,
+           executors::task::TaskExecutor &executor, size_t nDAGRunners);
+    ~Server();
+
+    Server &setSSLCertificates(const fs::path &cert, const fs::path &key);
+
+    void init(size_t threads = 1);
+
+    void start();
+
+    uint16_t getPort() const;
+
+    void shutdown();
+
+  private:
+    void createDescription();
+    void queueDAG_(DAGRunID runID, const TaskDAG &dag,
+                   const TaskParameters &taskParameters);
+
+    DAGGY_REST_HANDLER(handleReady);           // X
+    DAGGY_REST_HANDLER(handleQueryDAGs);       // X
+    DAGGY_REST_HANDLER(handleRunDAG);          // X
+    DAGGY_REST_HANDLER(handleValidateDAG);     // X
+    DAGGY_REST_HANDLER(handleGetDAGRun);       // X
+    DAGGY_REST_HANDLER(handleGetDAGRunState);  // X
+    DAGGY_REST_HANDLER(handleSetDAGRunState);  // X
+    DAGGY_REST_HANDLER(handleGetTask);         // X
+    DAGGY_REST_HANDLER(handleGetTaskState);    // X
+    DAGGY_REST_HANDLER(handleSetTaskState);    // X
+
+    bool handleAuth(const Pistache::Rest::Request &request);
+
+    Pistache::Http::Endpoint endpoint_;
+    Pistache::Rest::Description desc_;
+    Pistache::Rest::Router router_;
+
+    loggers::dag_run::DAGRunLogger &logger_;
+    executors::task::TaskExecutor &executor_;
+    ThreadPool runnerPool_;
+
+    std::mutex runnerGuard_;
+    std::unordered_map<DAGRunID, std::shared_ptr<DAGRunner>> runners_;
+  };
+}  // namespace daggy