Major frontend code cleanup (#452)

Many large changes, including:
- TypeScript enums are now string unions throughout
- Strong type-checking throughout the TS and Vue codebase
- Vue component props now all specify `as PropType<...>`
- Usage of annotated return types on all functions
- Sorting of JS import statements
- Explicit usage of Vue bind attribute function call arguments (`@click="foo"` is now `@click=(e) => foo(e)`)
- Much improved code quality related to the color picker
- Consistent camelCase Vue bind and v-model attributes
- Consistent Vue HTML attribute strings with single quotes
- Bug fix and clarity improvement with incorrect hint class parameters
- Empty Vue component objects like `props: {}` and `components: {}` removed

frontend/src/components/widgets/inputs/CheckboxInput.vue

@@ -80,9 +80,9 @@
 </style>
 
 <script lang="ts">
-import { defineComponent } from "vue";
+import { defineComponent, PropType } from "vue";
 
-import IconLabel from "@/components/widgets/labels/IconLabel.vue";
+import IconLabel, { IconName } from "@/components/widgets/labels/IconLabel.vue";
 
 export default defineComponent({
 	data() {
@@ -96,9 +96,9 @@ export default defineComponent({
 		},
 	},
 	props: {
-		checked: { type: Boolean, required: true },
-		icon: { type: String, default: "Checkmark" },
-		outlineStyle: { type: Boolean, default: false },
+		checked: { type: Boolean as PropType<boolean>, required: true },
+		icon: { type: String as PropType<IconName>, default: "Checkmark" },
+		outlineStyle: { type: Boolean as PropType<boolean>, default: false },
 	},
 	components: { IconLabel },
 });