chore(ci): add ci

[indirection42]

• add ci settings
• add new make targets
• Fix a lots of clippy warnings, most of which are caused by no_std and std settings. I use #[allow(dead_code)] or add conditional compilation cfg to solve them. I am not sure if it's the recommend practice. It's really verbose sometimes. For example, in scale_info crate, it's already use cfg_if to ensure that the exported APIs are stable in both std and no_std environments. However, when we use it, we still need to add conditional compilation #[cfg(not(feature="std"))] or #[allow(unused_imports)], otherwise clippy will complain.

close #14