Refine relocatable types

[elfenpiff]

Brief feature description

• [ ] RelocatableContainer requires a type alias to a Config type that is used in new(), new_uninit() and memory_size() to support containers consisting of multiple relocatable containers.
• [ ] Refactor Vec so that there are 3 version, FixedSizeVec, RelocatableVec and just Vec, just like the Queue
• [ ] Refactor ByteString so that there are 3 version, FixedSizeByteString, RelocatableByteString and just ByteString, just like the Queue
• [ ] iceoryx2-bb-elementary must become public API to enable users to implement their own relocatable types.
• [ ] RelocatableContainer requires a consuming drop or destroy method that requires an allocator as well to release the memory acquired with init.
• [ ] Think about a variant with a custom allocator - similar to the RelocatableContainer.