Add class renames to UpgradeShell

A few classes have moved around or were renamed. Add an ugprade shell
task for those. I also did some internal refactoring to reduce some
duplication and make code shorter.
Add missing path argument to the various tasks.
Fix mistakes.
Merge pull request #1560 from markstory/3.0-upgrade-shell-improvement

3.0 upgrade shell improvement
Fix a few coding standards errors.
Fix failing test.
Removed unused and deprecated constants.
added ext-mbstring as requirement.
Merge pull request #1578 from ADmad/3.0

Removed unused and deprecated constants.
Merge pull request #1579 from 0x20h/3.0-add-ext-mbstring-requirement

added ext-mbstring as composer requirement
Fix missing use
Fix typo in Database/ConnectionManager
Renamed configure reader classes.
Merge pull request #1581 from gold1/3.0-model-missing-use

Fix missing use
Merge pull request #1582 from gold1/3.0-connection-manager-fix-typo

Fix typo in Database/ConnectionManager
Merge pull request #1577 from ADmad/feature/configure-engine

Feature/configure engine
Start moving app config into an ini file.

This is a proof of concept that application configuration can be put
into static files quite easily.
Add sample email and email transport config.
Remove now unused config files.
Move app.ini to app.ini.php

Using a .php extension prevents webservers from accidentally serving the
configuration file as plain text. This is important for people who do
sloppy deployments where the contents of App/ are accessible from the
webserver.