Feature Request: Support MySQL Spatial Datatypes

Environment

Knex version: 0.95.12 Database + version: MySQL 8.0.27 OS: Windows

Feature discussion / request

1. Explain what is your use case

Being able to use MySQL Spatial Datatypes. Want to store districts as polygons and locations as points (SRID 4326).

1. Explain what kind of feature would support this

Can store geographic data.

1. Give some API proposal, how the feature should work

Here is the MySQL official docs:

https://dev.mysql.com/doc/refman/8.0/en/spatial-types.html

    knex.schema.createTable('table', (table) => {
      table.increments('id');
      table.polygon('area').srid(4326); //srid might be options?
    })

This pull request seems to implement some spatial datatypes, however they seem not supported on MySQL (at least polygon). https://github.com/knex/knex/pull/4776