stm32f1-hal 0.2.1

HAL for the STM32F1 family
Documentation
# stm32f1-hal

Because the design of [stm32f1xx-hal](https://github.com/stm32-rs/stm32f1xx-hal) is unsuitable for my needs and [stm32-hal](https://github.com/David-OConnor/stm32-hal) doesn't support the F1 series, I decided to write a new crate.
Many codes come from [stm32f1xx-hal](https://github.com/stm32-rs/stm32f1xx-hal).

Example is [here](https://github.com/jw-mcu-rust/stm32f1-hal/blob/main/examples/f103c8/src/main.rs).

## Design

Below are the design principles.
1. Readability is the most important.
    - We only write code a few times, but we read it countless times. Moreover, understanding the code is a necessary condition for maintaining it.
2. Concise is not equal to simple.
    - Fewer lines of code do not necessarily mean easier to read and understand.

Therefore, if a module is quite complex, I would not use a macro + generic approach, as it is too difficult to read.

Instead, I use a synchronization script to manage duplicate code across peripherals and a script to generate code for GPIO alternate function remapping.

## Note

This project is still in its early stages, with only a few features completed.