[EGD-5181] Add Circular and Logger buffers

Add RandomStringGenerator class.
Implement Circular and Logger buffers.
Add UTs for LoggerBuffer.

module-utils/circular_buffer/StringCircularBuffer.cpp

@@ -0,0 +1,55 @@
+// Copyright (c) 2017-2021, Mudita Sp. z.o.o. All rights reserved.
+// For licensing, see https://github.com/mudita/MuditaOS/LICENSE.md
+
+#include "StringCircularBuffer.hpp"
+
+std::pair<bool, std::string> StringCircularBuffer::get()
+{
+    if (isEmpty()) {
+        return {false, ""};
+    }
+
+    const std::string val = buffer[tail];
+    full                  = false;
+    tail                  = (tail + 1) % capacity;
+    --size;
+
+    return {true, val};
+}
+
+void StringCircularBuffer::put(const std::string &item)
+{
+    updateMembersBeforePut();
+    buffer[head] = item;
+    updateMembersAfterPut();
+}
+
+void StringCircularBuffer::put(std::string &&item)
+{
+    updateMembersBeforePut();
+    buffer[head] = std::move(item);
+    updateMembersAfterPut();
+}
+
+void StringCircularBuffer::reset()
+{
+    head = tail;
+    full = false;
+    size = 0;
+}
+
+void StringCircularBuffer::updateMembersAfterPut()
+{
+    head = (head + 1) % capacity;
+    full = head == tail;
+}
+
+void StringCircularBuffer::updateMembersBeforePut()
+{
+    if (full) {
+        tail = (tail + 1) % capacity;
+    }
+    else {
+        ++size;
+    }
+}