MPU9250 implementation

**Describe the problem you have/What new integration you would like**
Implementation of the mpu9250 9 axis sensor into ESPhome

**Please describe your use case for this integration and alternatives you've tried:**
Im looking to develop a home surveillance rover using an ESP32 cam as the main processor and ESPhome as the interface of choice. Having a 9axis sensor is fairly useful information for remote control of the rover. There are 6 axis alternative which I have not tried as I would prefer the extra compass information to be available

**Additional context**
Is this something to be considered for implementation or is the interest small enough to consider implementing it myself using the custom component function? If so, would it be of interest to then include it in the esphome API?

Start by reviewing ESPHome's existing sensor integrations and the MPU9250's requirements, including its compass data, then compare them with the six-axis alternatives mentioned in the request. Done means a supported MPU9250 integration is defined for ESPHome and its API availability is resolved.

Written by the indexing model from the issue text.