feat: Common component 추가- DropDownList

+import React from 'react';
+import styled from 'styled-components';
+import { dropdownListColorMap } from '../../lib/styles/palette';
+
+const DropDownListBlock = styled.div`
+  float: ${props => props.float || ''};
+  width: ${props => props.size || '40%'};
+`;
+
+const DropDownList = styled.ul`
+  padding: 0;
+  margin: 0;
+  background-color: ${props => dropdownListColorMap[props.color].background};
+  border: 2px solid ${props => dropdownListColorMap[props.color].borderColor};
+  box-sizing: border-box;
+  color: ${props => dropdownListColorMap[props.color].color};
+  font-size: 1.3rem;
+  font-weight: 500;
+  &:first-child {
+    padding-top: 0.5em;
+  }
+`;
+
+const ListItem = styled.li`
+  list-style: none;
+  padding-left: 1em;
+  padding-bottom: 0.3em;
+  border-bottom: 2px solid #e5e5e5;
+`;
+
+const DropDown = ({ children, color, float, size }) => {
+  return (
+    <DropDownListBlock color={color} float={float} size={size}>
+      <DropDownList color={color}>
+        <ListItem>{children}</ListItem>
+      </DropDownList>
+    </DropDownListBlock>
+  );
+};
+
+export default DropDown;