Improve Getting Started Experience

[thinkingserious]

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I updated my branch with the master branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

Contributing to Twilio

All third party contributors acknowledge that any contributions they provide will be made under the same open source license that the open source project is provided under.

Short description of what this PR does:

• Added a welcome message at the end of the installation process to guide the user on what to do next without RTM
• Added a login alias to expose project:add functionality at the base help level (e.g. twilio help)

[codecov]

Codecov Report

Merging #25 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #25   +/-   ##
=======================================
  Coverage   98.27%   98.27%           
=======================================
  Files          20       20           
  Lines         521      521           
=======================================
  Hits          512      512           
  Misses          9        9

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[aroach]

Approved!