Refactor handlers into separate packages and implement dependency injection.

IDK if this shit is good or even logical, but it works and I can wrap my head around it.

internal/handlers/home/mainPage.go

@@ -0,0 +1,23 @@
+package handlers_home
+
+import (
+	"CatsOfMastodonBotGo/internal"
+
+	"github.com/gin-gonic/gin"
+)
+
+type MainPageHandler struct{
+	AppContext *internal.AppContext
+}
+
+func NewMainPageHandler(appContext *internal.AppContext) *MainPageHandler {
+	return &MainPageHandler{
+		AppContext: appContext,
+	}
+}
+
+func (appContext *MainPageHandler) HomePageHandler(c *gin.Context) {
+	c.JSON(200, gin.H{
+		"YouAreOn": "HomePage",
+	})
+}