refactor: migrate web server to to axum

[robjtede]

blocked on #226

full axum migration, including router re-write

pros:

• –53 LoC
• Access to library of first- and third-party middleware.

cons:

• Incomplete, I havent' figured out how to support this behavior yet #164

tokei:

 Language            Files        Lines         Code     Comments       Blanks
===============================================================================
 Rust                   30         3899         3366           22          511
 |- Markdown             6           48            0           43            5
 (Total)                           3947         3366           65          516