First step in two-part process to rename directories to kallithea.
This first step is to change all references in the files where they refer
to the old directory name.

Imported some of the GPLv3'd changes from RhodeCode v2.2.5.

This imports changes between changesets 21af6c4eab3d and 6177597791c2 in
RhodeCode's original repository, including only changes to Python files and HTML.

RhodeCode clearly licensed its changes to these files under GPLv3
in their /LICENSE file, which states the following:
The Python code and integrated HTML are licensed under the GPLv3 license.

(See:
https://code.rhodecode.com/rhodecode/files/v2.2.5/LICENSE
or
http://web.archive.org/web/20140512193334/https://code.rhodecode.com/rhodecode/files/f3b123159901f15426d18e3dc395e8369f70ebe0/LICENSE
for an online copy of that LICENSE file)

Conservancy reviewed these changes and confirmed that they can be licensed as
a whole to the Kallithea project under GPLv3-only.

While some of the contents committed herein are clearly licensed
GPLv3-or-later, on the whole we must assume the are GPLv3-only, since the
statement above from RhodeCode indicates that they intend GPLv3-only as their
license, per GPLv3§14 and other relevant sections of GPLv3.

Added separate default permission for external_auth account
activation. This flag allows users to define separate option of how
activation of external_accounts should be performed.

fixed default permissions population during upgrades
- it often happen that introducing new permission
caused default permission to reset it's state to installation
default.
new version makes sure that only missing permissions are
created while leaving old defaults

follow Python conventions for boolean values

True and False might be singletons and the "default" values for "boolean"
expressions, but "all" values in Python has a boolean value and should be
evaluated as such. Checking with 'is True' and 'is False' is thus confusing,
error prone and unnessarily complex.

If we anywhere rely and nullable boolean fields from the database layer and
don't want the null value to be treated as False then we should check
explicitly for null with 'is None'.

Global permission update with "overwrite existing settings" shouldn't override private repositories.
It's to confusing to users, and private repos should be always private

implemented #663 Admin/permission: specify default repogroup perms
- added migration that adds new default permission for groups
- merged with patch from Vincent Caron

RhodeCode now has a option to explicitly set forking permissions. ref #508
- changed the way permissons on users groups behave. Now explicit set on user
is more important than permission set on users group

Update permissions from admin permissions menu, also overwrites defaults
for repos groups

Fixed permissions for users groups, group can have create repo permission now.
Some code refactor + pep8ify

fixed Example celery config to ampq,
fixed session problems on models and celery,
implemented one base model as a parent for other

implements #60, ldap configuration and authentication.
fixes settings to use settings Model

#50 on point cache invalidation changes.
Created cacheInvalidation table
cleaned up sa sessions from models, since it wasn't really needed.