docs: Add first-timers.md for newcomers

[daniloff200]

Closes #112

Fixes

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• 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

Short description of what this PR does:

This PR adds a First Timers.MD with a guideline for newcomers

[SendGridDX]

All committers have signed the CLA.

[codecov]

Codecov Report

Merging #116 into master will not change coverage.
The diff coverage is n/a.

@@          Coverage Diff           @@
##           master    #116   +/-   ##
======================================
  Coverage    84.7%   84.7%           
======================================
  Files           3       3           
  Lines         170     170           
======================================
  Hits          144     144           
  Misses         26      26

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[daniloff200]

Hey @thinkingserious ! Are you able and have time to review and merge this PR ?

[thinkingserious]

Hello @daniloff200,

Thanks again for the PR!

It's HACKTOBERFEST! We want to show our appreciation by sending you some special Hacktoberfest swag. If you have not already, could you please fill out this form so we can send it to you? Thanks!

Team SendGrid DX

[daniloff200]

hey @thinkingserious !
That's more than 1 year after last comment here :)

Can this PR be merged sometime?