Introduce ManagedMemory struct to simplify allocator usage

## Brief feature description

Using the `BumpAllocator` usually follows the pattern
```cxx
uint8_t memory[MEMORY_SIZE]; // create some memory
BumpAllocator memoryAllocator{memory, MEMORY_SIZE}; // use the allocator
```
The same is likely to be true for future allocators. This could be combined in a [struct](https://github.com/eclipse-iceoryx/iceoryx/pull/1820#discussion_r1064619210) like
```cxx
template
class ManagedMemory {
public:
ManagedMemory() : allocator{&this->memory, MEMORY_SIZE} {}
BumpAllocator& allocator();

private:
uint8_t memory[MEMORY_SIZE];
BumpAllocator allocator;
}
```

Start by locating BumpAllocator and its current usage patterns in the repository. Review how allocator ownership and initialization are handled, then determine where ManagedMemory belongs. Done means a reusable ManagedMemory template combines the backing buffer with its allocator without breaking existing allocator usage.

Written by the indexing model from the issue text.