feat: add http as smtp provider (#8545)

# Which Problems Are Solved

Send Email messages as a HTTP call to a relay, for own logic on handling
different Email providers

# How the Problems Are Solved

Create endpoints under Email provider to manage SMTP and HTTP in the
notification handlers.

# Additional Changes

Clean up old logic in command and query side to handle the general Email
providers with deactivate, activate and remove.

# Additional Context

Partially closes #8270

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/command/instance.go

@@ -116,7 +116,7 @@ type InstanceSetup struct {
 	}
 	EmailTemplate     []byte
 	MessageTexts      []*domain.CustomMessageText
-	SMTPConfiguration *smtp.Config
+	SMTPConfiguration *SMTPConfiguration
 	OIDCSettings      *OIDCSettings
 	Quotas            *SetQuotas
 	Features          *InstanceFeatures
@@ -124,6 +124,15 @@ type InstanceSetup struct {
 	Restrictions      *SetRestrictions
 }
 
+type SMTPConfiguration struct {
+	Description    string
+	SMTP           smtp.SMTP
+	Tls            bool
+	From           string
+	FromName       string
+	ReplyToAddress string
+}
+
 type OIDCSettings struct {
 	AccessTokenLifetime        time.Duration
 	IdTokenLifetime            time.Duration
@@ -440,7 +449,7 @@ func setupOIDCSettings(commands *Commands, validations *[]preparation.Validation
 	)
 }
 
-func setupSMTPSettings(commands *Commands, validations *[]preparation.Validation, smtpConfig *smtp.Config, instanceAgg *instance.Aggregate) {
+func setupSMTPSettings(commands *Commands, validations *[]preparation.Validation, smtpConfig *SMTPConfiguration, instanceAgg *instance.Aggregate) {
 	if smtpConfig == nil {
 		return
 	}