many many updates (check commit detail)

- updated dependencies
  - bumped react version 17 -> 18
- changed navbar button tag from `a` to `button`
- added locale info to url (made sure same url = same content)
- fixed 0 gettingconsidered as "unknown length" for
  word count in `PostCard`
- moved functions from `Page.tsx` to `helper.ts`
- added "translation not available" page

.eslintrc

@@ -11,7 +11,7 @@
 			"tryExtensions": [".js", ".jsx", ".json"]
 		},
 		"react": {
-			"version": "17.0"
+			"version": "18.0"
 		}
 	},
 	"parser": "@typescript-eslint/parser",
@@ -21,7 +21,7 @@
 		},
 		"sourceType": "module"
 	},
-	"plugins": ["react", "@typescript-eslint"],
+	"plugins": ["@typescript-eslint"],
 	"rules": {
 		"@typescript-eslint/no-empty-interface": "off",
 		"@typescript-eslint/explicit-module-boundary-types": "off",