feat: send test mail (#7968)

# Which Problems Are Solved

- Zitadel doesn't have a way to test SMTP settings either before
creating a new provider or once the SMTP provider has been created.
- Zitadel SMTP messages can be more informative for usual errors

# How the Problems Are Solved

- A new step is added to the new/update SMTP provider wizard that allows
us to test a configuration. The result is shown in a text area.
- From the table of SMTP providers you can test your settings too.
- The email address to send the email is by default the email address
for the logged in user as suggested.
- Some of the SMTP error messages have been changed to give more
information about the possible situation. For example: could not contact
with the SMTP server, check the port, firewall issues... instead of
could not dial

Here's a video showing this new option in action:


https://github.com/zitadel/zitadel/assets/30386061/50128ba1-c9fa-4481-8eec-e79a3ca69bda

# Additional Changes

Replace this example text with a concise list of additional changes that
this PR introduces, that are not directly solving the initial problem
but are related.
For example:
- The docs explicitly describe that the property XY is mandatory
- Adds missing translations for validations.

# Additional Context

- Closes #4504

docs/docs/guides/manage/console/default-settings.mdx

@@ -107,6 +107,14 @@ To configure your custom SMTP please fill the following fields:
 
 <img src="/docs/img/guides/console/smtp.png" alt="SMTP" width="800px" />
 
+While you create/update a SMTP provider you have the chance to test your SMTP configuration
+
+<img src="/docs/img/guides/console/smtp_test.png" alt="SMTP" width="800px" />
+
+In the SMTP providers table you can hover on a provider row to show buttons that allow you to activate/deactivate a provider, test your smtp settings and delete a provider
+
+<img src="/docs/img/guides/console/smtp_table.png" alt="SMTP" width="800px" />
+
 ### SMS
 
 No default provider is configured to send some SMS to your users. If you like to validate the phone numbers of your users make sure to add your twilio configuration by adding your Sid, Token and Sender Number.