Add new project button to Sidebar Header

[mpabarca]

Description

Add "Add new project" button to Sidebar Header that redirects to shape-docs wiki page.

Motivation and Context

• A small button on Shape Docs to get people started on the platform it become more relevant cause is been open the service to more people.

In order to do that is was added a new .env variable NEXT_PUBLIC_SHAPE_DOCS_PROJECT_WIKI_URL that has the URL of the wiki page.

Screenshots:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

[github-actions]

⚠️ It looks like .env.example has changed. Remember to update the Setting Environment Variables article accordingly.

[mpabarca]

@ulrikandersen @simonbs
Once we merge this change, we need to add the .env key NEXT_PUBLIC_SHAPE_DOCS_PROJECT_WIKI_URL to the variables on the deployment platform (AWS?)

[simonbs]

Following our talk yesterday, I have moved the button that opens the wiki into the user menu in the lower-left corner and renamed it "Help".

It's now using an environment variable named NEXT_PUBLIC_SHAPE_DOCS_HELP_URL instead of NEXT_PUBLIC_SHAPE_DOCS_PROJECT_WIKI_URL, as the button doesn't have to link to our wiki but could be configured to link to any internal documentation.

The "Add New Project" button has been left in the codebase but commented out as we'll need it soon.

[mpabarca]

LGTM