feat(mysql): add optional authPlugin parameter for MySQL user creation

[ymaniukevich]

Description of your changes

This pull request adds the ability to specify an authentication plugin when creating MySQL users. This enhancement allows users to define which authentication method should be used, providing greater flexibility and compatibility with various MySQL setups.
Supported Authentication Plugins: mysql_native_password, caching_sha2_password, AWSAuthenticationPlugin.

Fixes #106

I have:

• Read and followed Crossplane's [contribution process].
• Run make reviewable to ensure this PR is ready for review.

How has this code been tested

make build
make reviewable
make e2e

I built and tested the package locally using the following resources as well .

apiVersion: mysql.sql.crossplane.io/v1alpha1
kind: User
metadata:
  name: we1
spec:
  forProvider:
    resourceOptions:
      maxQueriesPerHour: 1000
      maxUpdatesPerHour: 1000
      maxConnectionsPerHour: 100
      maxUserConnections: 10
  writeConnectionSecretToRef:
    name: we1
    namespace: default
---
apiVersion: mysql.sql.crossplane.io/v1alpha1
kind: User
metadata:
  name: we2
spec:
  forProvider:
    authPlugin: caching_sha2_password
  writeConnectionSecretToRef:
    name: we2
    namespace: default
---
apiVersion: mysql.sql.crossplane.io/v1alpha1
kind: User
metadata:
  name: we3
spec:
  forProvider:
    authPlugin: AWSAuthenticationPlugin
  writeConnectionSecretToRef:
    name: we3
    namespace: default