Description

In the current CLP, we use unique pointers of C-style arrays across the code base whenever we need a fix-sized buffer. This violates clang-tidy suggestions which advocate deprecating C-style arrays. However, existing std containers have limitations to use.

• For std::vector, it is hard to control the underlying storage. The storage size is controlled by its capacity but not the size. Also, the vector can't be made immutable to use the storage as a buffer to receive data (such as the use case in NetworkReader). This means there's no way to avoid reallocation/resizing by mistakes. Declaring a vector and using its underlying data() buffer will not provide any safety.
• For std::array, the size must be given in the compile time.

Therefore, we introduce our own implementation of arrays, clp::Array, which is a fix-sized array where the size is determined during the run-time. We use std::unique_ptr to manage the underlying buffer storage (which is allocated in the heap), and a member to keep track of the size to avoid out-of-bound access. This PR implements the basic features of our array, including methods for random access and iterators. At this stage, the underlying element of the array must be default initializable so that we don't have to implement the initializer list constructor yet.
APIs of this class are designed to mirror std containers.

Validation performed

• Ensure all workflows can be built.
• Add unit tests to cover the basic usages against fundamental types and default constructible aggregated types, and ensure the iterator is compatible with std algorithms.