Add configurable raw limit

[alexellis]

Signed-off-by: Alex Ellis (OpenFaaS Ltd) alexellis2@gmail.com

Description

Add configurable raw limit

Motivation and Context

This change means users can send a raw body of over 100KB, previously the body-parser middleware was restricting this size.

Which issue(s) this PR fixes

Fixes: #245 Closes: #246

How Has This Been Tested?

Tested by the user in #245 and by another user on Slack who also asked for this today.

Types of changes

• [x] 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 change)
• [ ] Version change (see: Impact to existing users)

Impact to existing users

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.

A change will be required in the openfaas/docs repo.