- Aligned the vertex/edge descriptor types to allow:
  - Proper implicit conversion from non-const to const variant
  - Comparison between a const and non-const variants
- Refactored the `graph` class and the internal implementation types to define and utilize const and non-const element descriptors based on the graph's constness
- Relaxed the `c_graph` concept to allow multiple value/type categories of the `graph` class
- Introduced helper typedefs to easily extract the typedefs from a graph type in generic contexts
- Refactored the internal specialized implementation types to use the explicit object parameter feature in order to be used as mixin base types instead of simple static method dispatchers
- Aligned the algorithm implementations to work with the new, aligned graph implementation

- Aligned the hyperedge descriptor type to allow:
  - Proper implicit conversion from non-const to const variant
  - Comparison between a const and non-const variants
- Refactored the `hypergraph` class to define and utilize const and non-const element descriptors based on the hypergraph's constness
- Relaxed the `c_hypergraph` concept to allow various value/type categories of the `hypergraph` class
- Introduced helper typedefs to easily extract the typedefs from a hypergraph type in generic contexts
- Aligned the algorithm implementations to work with the new, aligned graph implementation
- Additional cleanup of the GL module

In both GL and HGL modules:
- Added an `Extension` template parameter and an `ext` member to the `search_node` types
- Aligned the `dfs` templates to properly utilize an extended `search_node` type to perform a true post-order execution of the `post_visit` callback
- Replaced the use of `std::vector` for single-root ranges in concrete algorithms with `std::array`

In the GL module:
- Replaced the dedicated `dijkstra_search_node` type with a simple extension of the generic `search_node` type

In the HGL module:
- Replaced the old `search_tree` alias for a vector of search nodes with a dedicated `search_tree` type with its dedicated, smaller nodes

Removed trailing new line characters in graph/hypergraph stream output

- Changed the callback type requirements for the algorithm templates to accept a `search_node` instance instead of relying on raw IDs
- Aligned the algorithm callback builders and concrete algorithms to use the new `search_node` callback approach