Configuration transposed into environment variables (#82)

Configuration file not required anymore
DIUN_DB env var renamed DIUN_DB_PATH
Only accept duration as timeout value (10 becomes 10s)
Add getting started doc
Enhanced documentation
Add note about test notifications (#79)
Improve configuration management
Fix telegram init
All fields in configuration now camelCased
Improve configuration validation
Update doc
Update FAQ

Co-authored-by: CrazyMax <crazy-max@users.noreply.github.com>

internal/model/notif_webhook.go

@@ -0,0 +1,28 @@
+package model
+
+import (
+	"time"
+
+	"github.com/crazy-max/diun/v3/pkg/utl"
+)
+
+// NotifWebhook holds webhook notification configuration details
+type NotifWebhook struct {
+	Endpoint string            `yaml:"endpoint,omitempty" json:"endpoint,omitempty" validate:"required"`
+	Method   string            `yaml:"method,omitempty" json:"method,omitempty" validate:"required"`
+	Headers  map[string]string `yaml:"headers,omitempty" json:"headers,omitempty" validate:"omitempty"`
+	Timeout  *time.Duration    `yaml:"timeout,omitempty" json:"timeout,omitempty" validate:"required"`
+}
+
+// GetDefaults gets the default values
+func (s *NotifWebhook) GetDefaults() *NotifWebhook {
+	n := &NotifWebhook{}
+	n.SetDefaults()
+	return n
+}
+
+// SetDefaults sets the default values
+func (s *NotifWebhook) SetDefaults() {
+	s.Method = "GET"
+	s.Timeout = utl.NewDuration(10 * time.Second)
+}