Add MySQL Aspire Component

[eerhardt]

We will probably have both EF and non-EF components (just like the other database components).

https://www.nuget.org/packages/MySql.EntityFrameworkCore
https://www.nuget.org/packages/MySql.Data

[bgrainger]

I am incredibly biased here, since I am the author of MySqlConnector, but I would strongly advocate for https://www.nuget.org/packages/MySqlConnector/ to be the preferred library for MySQL. Some reasons:

1. Better License: MIT instead of GPL
2. OSS development at https://github.com/mysql-net/MySqlConnector; MySql.Data releases code snapshots quarterly but does not have an open development process
3. MySqlConnector supports DbBatch, DbDataSource, and other new ADO.NET abstractions that have been introduced in recent .NET versions; MySql.Data does not.
4. MySqlConnector has been async-first since the earliest versions; MySql.Data lacked any async support for the last ten years, then shipped with serious async bugs for six months.
5. MySqlConnector has a much more robust suite of integration tests and fewer outstanding known issues.
6. Popularity: the community has recognized the above advantages and MySqlConnector has more downloads even though it's a newer package.

I'm sure Aspire could have components for both MySqlConnector and MySql.Data, but if it's going to be an "opinionated stack" (emphasis in original), I know which opinion I want it to have. 😀

[bgrainger]

7. AspNetCore.HealthChecks.MySql already uses MySqlConnector.

[eerhardt]

Re-opening to track adding an EF based component.

[davidfowl]

Putting this in preview2 but it'll likely make it for preview3 unless @bgrainger can get this done before next Tuesday 😄