http: Remove default arguments from prepare callback function.

vcs: Raise exception if unknown protocol specified for vcs server protocol.

http: Remove 'pyro4' default values from function arguemnts in vcs init. #4237

http: Use http as default setting when sanitize config values. Part of #4237

vcs: Set default settings to HTTP in ini files. Part of #4237

tests: add test for pull request with multiple commits and reflect peppercorn usage in other pull request tests

pullrequests: added peppercorn sequence start/end markers to commit range list to fix bug where pull requests with multiple commits were submitting only one commit

dev-env: Remove flake8 target from makefile. We previously removed flake8 from our development environment. This is a follow up which removes it also from the makefile.

global settings: add a new template for flash filtering

helpers: flash messages can now carry additional information in json format