math: add more constants

[Wertzui123]

* Golden ratio, sqrt(2 and 3), ln(2), ...
A lot of constants have already been implemented by @kelanialiyu in #15. Still, there's always room for more, which is why I'm leaving this issue open for now.

They can be implemented like pi and e using functions for now (although this is very inefficient and we should figure out a better solution soon).

[kelanialiyu]

can you assign this to me

[Wertzui123]

Glad to hear that you're planning on contributing to ASPL!
This issue is rather open-ended, as one can always add more constants, so I don't think it makes sense to assign people to it. Just fork and open a PR.

[Wertzui123]

A lot of constants have now been implemented by @kelanialiyu in #15. Still, there's always room for more, which is why I'm leaving this issue open for now.