Add support for Aria2

[wszdexdrf]

Adding support for Aria2 would be a big improvement, due to the performance improvements implemented in Aria2 for faster downloads of multiple files. Given the current working of the library, this wouldn't require large changes.

Relevent Resources:

• https://aria2.github.io/manual/en/html/index.html
• https://aria2.github.io/manual/en/html/libaria2.html