Support PMSA003A

**Describe the problem you have/What new integration you would like**

I have the bare PMSA003A sensor that I would like to collect data from.
Data Sheet: http://m.eleparts.co.kr/data/goods_old/data/PMSA003.pdf

There are 10 pins coming out of the device but the only required ones are:

- Pin 1: Vcc (5v)
- Pin 3: GND
- Pin 7: UART RX
- Pin 9: UART TX

**Please describe your use case for this integration and alternatives you've tried:**

There are two components that are almost right but can't be used:

- PMSA003I: https://esphome.io/components/sensor/pmsa003i.html
- Has an I2C adapter board, mine is just the sensor without the attached board
- PMSX003: https://esphome.io/components/sensor/pmsx003.html
- Does not support the "A" series

**Additional context**

Start with the PMSA003 datasheet and compare the existing PMSA003I and PMSX003 integrations linked in the request. Determine the protocol and differences needed for the bare PMSA003A, then verify that data can be collected through its listed UART pins and that the new integration is covered by appropriate tests.

Written by the indexing model from the issue text.