Refactor application structure and initialize core components

I decided to rewrite the program taking into account the experience gained.

internal/gui/view/convertor.go

@@ -0,0 +1,33 @@
+package view
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/lang"
+	"fyne.io/fyne/v2/widget"
+)
+
+func Convertor() fyne.CanvasObject {
+	form := newFormConvertor()
+
+	converterVideoFilesTitle := lang.L("converterVideoFilesTitle")
+	return widget.NewCard(converterVideoFilesTitle, "", container.NewVScroll(form.getForm()))
+}
+
+type formConvertor struct {
+	form  *widget.Form
+	items []*widget.FormItem
+}
+
+func newFormConvertor() *formConvertor {
+	f := widget.NewForm()
+	f.SubmitText = lang.L("converterVideoFilesSubmitTitle")
+
+	return &formConvertor{
+		form: f,
+	}
+}
+
+func (f *formConvertor) getForm() *widget.Form {
+	return f.form
+}