LogManager: implement system module, client api, logging api (#1617)

Some notes:

* Unless `atmosphere!enable_log_manager` is true, Nintendo's log manager will be used instead.
  * This prevents paying memory costs for LM when not enabling logging.
  * To facilitate this, Atmosphere's log manager has a different program id from Nintendo's.
  * `atmosphere!enable_htc` implies `atmosphere!enable_log_manager`.
* LogManager logs to tma, and the SD card (if `lm!enable_sd_card_logging` is true, which it is by default).
* Binary logs are saved to `lm!sd_card_log_output_directory`, which is `atmosphere/binlogs` by default.

libraries/libstratosphere/source/lm/srv/lm_log_service_impl.cpp

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2018-2020 Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stratosphere.hpp>
+#include "lm_log_service_impl.hpp"
+#include "lm_logger_impl.hpp"
+
+namespace ams::lm::srv {
+
+    namespace {
+
+        struct LoggerImplAllocatorTag;
+        using LoggerAllocator     = ams::sf::ExpHeapStaticAllocator<3_KB, LoggerImplAllocatorTag>;
+        using LoggerObjectFactory = ams::sf::ObjectFactory<typename LoggerAllocator::Policy>;
+
+        class StaticAllocatorInitializer {
+            public:
+                StaticAllocatorInitializer() {
+                    LoggerAllocator::Initialize(lmem::CreateOption_None);
+                }
+        } g_static_allocator_initializer;
+
+    }
+
+    Result LogServiceImpl::OpenLogger(sf::Out<sf::SharedPointer<::ams::lm::ILogger>> out, const sf::ClientProcessId &client_process_id) {
+        /*  Open logger. */
+        out.SetValue(LoggerObjectFactory::CreateSharedEmplaced<::ams::lm::ILogger, LoggerImpl>(this, client_process_id.GetValue()));
+        return ResultSuccess();
+    }
+
+}