feat(mysql): add GEOMETRY support

[mirromutth]

Resolve #2735
Also may help to resolve issue in #166

Allows users enable geometry feature to use type geo_types::Geometry<f64> for GEOMETRY fields in MySQL.

Use ColumnType::Blob due to MySQL does not allow to execute prepared statement with a ColumnType::Geometry parameter, or am I missing something?

Based on geozero provided by georust

[heksesang]

Any plans to merge this soon?

[abonander]

geozero provides integration with SQLx on their end so this would just introduce a dependency cycle.

I'm happy with it living there for the time being.

[gmli]

Hi @abonander , if I understand correctly the documentation of geozero, Geometry for MySQL (with sqlx) isn’t supported on their side. Do you suggest to add this feature on the geozero project ?

[abonander]

Yes, since they've already added a sqlx feature. Otherwise it's just asking for annoying dependency cycle errors in Cargo.

[gmli]

Thank you.
@mirromutth did you planned to do it on geozero ?