Throw an error when environmental root directory is missing

[kchresfield]

Describe the bug
If the environment root directory is not found, no error is thrown it exits out without a message

To Reproduce
Steps to reproduce the behavior:

1. In the controller/projects file, set the rootDirectory variable to a root path that does not exist.
   

   opspark/controller/projects.js

   Line 17 in e851311

   let rootDirectory = `${home()}/environment`;

2. fs.readdirSync(${rootDirectory}/) resolves to undefined, code does not break or error thrown.

   opspark/controller/projects.js

   Line 26 in e851311

   githubDir = fs.readdirSync(`${rootDirectory}/`)

Expected behavior
Expected an error to be printed to the console or terminal

Desktop (please complete the following information):

• OS: iOS
• Browser: Chrome
• Version: Chrome 77, ospark 3.1.0

Additional context
Can be resolved with a try and catch. Wrapping the githubDir variable in a try and an error in a catch.

else if (codenvyUser) {
  rootDirectory = codenvyUser;
  try {
    githubDir = fs.readdirSync(`${rootDirectory}/`)
      .filter(dir => /[\w]+\.github\.io/.test(dir))[0];
  } catch (err) {
    console.log(err);
  }