* [app] Add testcases for musl libc

* [feat] Support for loading musl app and entering main function

* [syscall] Add some necessary syscalls for base musl applications

* [ci] Add deploy CI and update test CI

* [syscall] Split syscalls into multiple files according to the syscall categories

* [build] Add configuration for user space

* [loader] Move IO methods to axmem module and simplify codes.

* [CI] Continue on error for clippy and fmt test

* [CI] Update dependencies for qemu build

* [style] Fix code style according to the PR content

* [fix] Set the base address for static-ELF as 0 by default

* [feat] Support complie and test musl app on rv64 and aarch64

* [config] Fix the format for config file

* [style] format the code style

* [style] format crate import style:
```rust
mod sub_mod1;
mod sub_mod2;

use core::foo::Bar;
use alloc::bar::Foo;

use ext_crate::bar;

use crate::baz;
use self::sub_mod1::foo;
use super::sup_mod::qux;

pub use ...
```

* [style] format code style