fix: Added sideEffects field to package.json

See: https://webpack.js.org/guides/tree-shaking/

Summary, new sideEffects field helps with dead code elimination with
webpack and helps build performance since it doesn't need to parse it
with terser.

I tested a really simple example in CRA that was just:

```diff
 import React from "react";
 import logo from "./logo.svg";
+import { Button } from "react-md";
 import "./App.css";

 function App() {
   return (
     <div className="App">
       <header className="App-header">
         <img src={logo} className="App-logo" alt="logo" />
         <p>
           Edit <code>src/App.js</code> and save to reload.
         </p>
+        <Button>Hello</Button>
```

```diff
 import React from "react";
 import ReactDOM from "react-dom";
+import "react-md/dist/css/react-md.blue-teal-400-dark.min.css";
 import "./index.css";
```

Where I'd build with and without the react-md styles being imported. I
think these stats will be negligible once more components are being
used, but here's the few results with my MacBook.

Current build stats:

```sh
 # without css
 # average build time ~12s
File sizes after gzip:

  205.54 KB  build/static/js/2.646bee91.chunk.js
  777 B      build/static/js/runtime-main.b9cd606a.js
  682 B      build/static/js/main.909a8f83.chunk.js
  547 B      build/static/css/main.5f361e03.chunk.css
```

```sh
 # with css
 # average build time ~13s
File sizes after gzip:

  205.54 KB  build/static/js/2.06a718b5.chunk.js
  15.84 KB   build/static/css/2.c416ebf1.chunk.css
  777 B      build/static/js/runtime-main.b9cd606a.js
  685 B      build/static/js/main.5a2d7e96.chunk.js
  547 B      build/static/css/main.5f361e03.chunk.css
```

With `"sideEffects": ["dist/**/*"]`:

```sh
 # without css
 # average build time ~8s
File sizes after gzip:

  45.79 KB (-159.75 KB)  build/static/js/2.5e21dda9.chunk.js
  777 B                  build/static/js/runtime-main.b9cd606a.js
  672 B (-10 B)          build/static/js/main.5c471371.chunk.js
  547 B                  build/static/css/main.5f361e03.chunk.css

 # stats compared to previous without css build
```

```sh
 # with css
 # average build time ~9
File sizes after gzip:

  45.8 KB (-159.75 KB)  build/static/js/2.043fb57c.chunk.js
  15.84 KB              build/static/css/2.c416ebf1.chunk.css
  777 B                 build/static/js/runtime-main.b9cd606a.js
  673 B (-12 B)         build/static/js/main.5e1aaad3.chunk.js
  547 B                 build/static/css/main.5f361e03.chunk.css

 # stats compared to previous with css build
```

Author: mlaursen

packages/alert/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/app-bar/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/autocomplete/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/avatar/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/badge/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/button/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/card/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/chip/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/dialog/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",

packages/divider/package.json

@@ -9,6 +9,7 @@
   "main": "./lib/index.js",
   "module": "./es/index.js",
   "types": "./types/index.d.ts",
+  "sideEffects": ["dist/**/*"],
   "files": [
     "es/*",
     "lib/*",