refactor(card-list): migrate from js to tsx

the card list components has been migrated to typescript
react component. For a given card list item, if the image is provided,
then the alt props must be passed as GastbyImage requires the alt props

Refs: ethereum#6392

src/components/CardList.tsx

@@ -71,18 +71,27 @@ const Image = styled(GatsbyImage)`
   margin-top: 4px;
 `
 
-export interface ICardListItem {
+type ForbidOptional<T = {}> = {
+  [P in keyof T]?: never
+}
+
+type OptionalCardImageProp = {
+  image: string
+  alt: string
+}
+
+type CardImage = ForbidOptional<OptionalCardImageProp>
+
+export type CardListItem = {
   title: string
-  description: string
+  description?: string
   caption?: string
-  link: string
-  image?: string
-  alt?: string
-  id: string | number
-}
+  link?: string
+  id?: string | number
+} & (OptionalCardImageProp | CardImage)
 
 export interface IProps {
-  content: Array<ICardListItem>
+  content: Array<CardListItem>
   className?: string
   clickHandler?: (idx: string | number) => void
 }