Add type definitions for react-lazyload package. (#16807)

* Add type definitions for `react-lazyload` package.

* fix lint error.

* fix TypeScript Version

types/react-lazyload/index.d.ts

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+// Type definitions for react-lazyload ver 2.2
+// Project: https://github.com/jasonslyvia/react-lazyload
+// Definitions by: m0a <https://github.com/m0a>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+// TypeScript Version: 2.1
+
+import {Component} from 'react';
+
+export interface LazyLoadProps {
+    once?: boolean;
+    height?: number | string;
+    offset?: number | string;
+    overflow?: boolean;
+    scroll?: boolean;
+    children?: JSX.Element;
+    throttle?: number | boolean;
+    debounce?: number | boolean;
+    placeholder?: Node;
+    unmountIfInvisible?: boolean;
+}
+
+export default class LazyLoad extends Component<LazyLoadProps, {}> {
+    constructor(props: LazyLoad);
+}
+
+export  function lazyload(option: {}): LazyLoad;

types/react-lazyload/react-lazyload-tests.tsx

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+import * as React from "react";
+import LazyLoad from "react-lazyload";
+
+interface State {
+    arr: string[];
+}
+
+class Normal extends React.Component<{}, State> {
+    constructor() {
+        super();
+        let arr: string[] = [];
+        for (let i = 0; i < 200; i++) {
+            arr.push(`${i}`);
+        }
+        this.state = { arr };
+    }
+    render() {
+        return (
+            <div>
+                {this.state.arr.map((el, index) => {
+                    return (
+                        <LazyLoad once={true} key={index} height={200} offset={50}>
+                            <p id={`${index}`}  >
+                                count={index + 1}
+                            </p>
+                        </LazyLoad>
+                    );
+                })}
+            </div>
+        );
+    }
+}

types/react-lazyload/tsconfig.json

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+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": [
+            "es6",
+            "dom"
+        ],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": [
+            "../"
+        ],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true,
+        "jsx": "react"
+    },
+    "files": [
+        "index.d.ts",
+        "react-lazyload-tests.tsx"
+    ]
+}

types/react-lazyload/tslint.json

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+{ "extends": "dtslint/dt.json" }