Extract scene functions to their respective modules (#208)

- Also, extract utilities into utils module -- capitalizeString, getDateTime, isInputLike

src/utils.ts

@@ -0,0 +1,25 @@
+export function getDateTime() {
+  const date = new Date();
+  const year = date.getFullYear();
+  const month = date.getMonth() + 1;
+  const day = date.getDate();
+  const hr = date.getHours();
+  const min = date.getMinutes();
+  const secs = date.getSeconds();
+
+  return `${year}${month}${day}${hr}${min}${secs}`;
+}
+
+export function capitalizeString(str: string) {
+  return str.charAt(0).toUpperCase() + str.slice(1);
+}
+
+export function isInputLike(
+  target: Element | EventTarget | null
+): target is HTMLInputElement | HTMLTextAreaElement | HTMLSelectElement {
+  return (
+    target instanceof HTMLInputElement ||
+    target instanceof HTMLTextAreaElement ||
+    target instanceof HTMLSelectElement
+  );
+}