feat: Notifiers CRUD (#337)

* introduce scaffold for new models

* wip: shoutrrr wrapper (may remove)

* update schema files

* gen: ent code

* gen: migrations

* go mod tidy

* add group_id to notifier

* db migration

* new mapper helpers

* notifier repo

* introduce experimental adapter pattern for hdlrs

* refactor adapters to fit more common use cases

* new routes for notifiers

* update errors to fix validation panic

* go tidy

* reverse checkbox label display

* wip: notifiers UI

* use badges instead of text

* improve documentation

* add scaffold schema reference

* remove notifier service

* refactor schema folder

* support group edges via scaffold

* delete test file

* include link to API docs

* audit and update documentation + improve format

* refactor schema edges

* refactor

* add custom validator

* set validate + order fields by name

* fix failing tests

.scaffold/model/templates/model.go

@@ -0,0 +1,40 @@
+package schema
+
+import (
+	"entgo.io/ent"
+
+	"github.com/hay-kot/homebox/backend/internal/data/ent/schema/mixins"
+)
+
+type {{ .Scaffold.model }} struct {
+	ent.Schema
+}
+
+func ({{ .Scaffold.model }}) Mixin() []ent.Mixin {
+	return []ent.Mixin{
+		mixins.BaseMixin{},
+		{{- if .Scaffold.by_group }}
+		GroupMixin{ref: "{{ snakecase .Scaffold.model  }}s"},
+		{{- end }}
+	}
+}
+
+// Fields of the {{ .Scaffold.model }}.
+func ({{ .Scaffold.model }}) Fields() []ent.Field {
+	return []ent.Field{
+		// field.String("name").
+	}
+}
+
+// Edges of the {{ .Scaffold.model }}.
+func ({{ .Scaffold.model }}) Edges() []ent.Edge {
+	return []ent.Edge{
+		// edge.From("group", Group.Type).
+	}
+}
+
+func ({{ .Scaffold.model }}) Indexes() []ent.Index {
+	return []ent.Index{
+		// index.Fields("token"),
+	}
+}