Customer Success handbook clean-up

Some updates for copy and to linkify the customer success handbook resources.  Content will expand further in development

See merge request !3972

removed underscore dupe directory 

How to keep a forked project up to date with its origin

Closes https://gitlab.com/gitlab-com/blog-posts/issues/299

See merge request !3952

Combined emails to new hires

See merge request !4003

Fixed the layout of the partners page

Added the header that declares the type of layout of this page, also fixed a minor markdown typo

How it looks now:
![Partners_GitLab_Before](/uploads/b0af88e1330f9de0ca029aad5a9e385b/Partners_GitLab_Before.png)

How it would look after:
![Partners_GitLab](/uploads/5a970fe4d189e7194a613b4c4f67c04a/Partners_GitLab.png)

See merge request !4018

Add Appearin to handbook

adding appear.in as a chat option since many of us are using it now!

See merge request !3976

Regional Director Sales

Planning for the growth of the sales team in 2017 to hit our revenue goals, posting for a sales leader to hire and build out a team in the US.  This is part of the headcount and plan for 2017.

cc/ @jparrow

See merge request !3803

Add Letter of Adjustment

Once the MR is merged, I will make the document viewable to anyone with the link cc @jparrow @amatthews

See merge request !3579

add INC W2 Contractor and Hourly Employee agreements

Once the contracts are approved to go live, I will make them viewable to anyone with the link

cc @sytses @pmachle @ernstvn @jparrow @amatthews

See merge request !3492

blog image for yc office hours

See merge request !3356

move update bamboohr information

Moving higher up in onboarding to ensure that it is done prior to the first day. This will help alleviate gathering information on day one.

See merge request !4046

Updated Content Team expertise

Closes #911

See merge request !3798

Hacker News jobs.

/cc @kirstenabma @brittanyr 

Let's post our support lead job after this is merged.

See merge request !4044

Update online marketing manager

Reviewing job descriptions, does this seem reasonable? /cc @mitchellwright @hanktaylor @sytses @pmachle @ernstvn 

See merge request !2537

add coding classes to spending company money

See merge request !4028

Edits to Hiring Process pt. 1

This is the first of a 3 part change to the hiring process.
1. Clarify & update existing process
2. Restructure Hiring page
3. Outline interview process for each role on the unique job
description page

See merge request !4029

update reports to

Also, updated in BambooHR.

See merge request !4040

Added markdown page layout

See merge request !4038

Simplify writing process.

Simplify the process, inspired by https://www.digitalocean.com/community/get-paid-to-write

See merge request !4014

Copy edit Issue Bash post

Fixed typo in Mark's name

Closes #964

See merge request !4034