Align and update the outdated ini files and templates

Change default database for development.ini to sqlite

db: tweak configuration of branding self references

For RhodeCode compatibility:
echo "BRAND='rhodecode'" > kallithea/brand.py

SETTINGS_PREFIX for identifiers (e.g., db table names) incl. project's name.

kallithea.SETTINGS_PREFIX is a variable string used as a prefix for specific
external identifiers, such as database table names (and likely later form
fields), so that the name of the project need not necessarily be encoded into
data.

This setting is configurable so that compatibility with old, similar
databases can be maintained at the users' request.

Correct licensing information in individual files.

The top-level license file is now LICENSE.md.

Also, in various places where there should have been joint copyright holders
listed, a single copyright holder was listed. It does not appear easy to add
a link to a large list of copyright holders in these places, so it simply
refers to the fact that various authors hold copyright.

In future, if an easy method is discovered to link to a list from those
places, we should do so.

Finally, text is added to LICENSE.md to point to where the full list of
copyright holders is, and that Kallithea as a whole is GPLv3'd.

Second step in two-part process to rename directories.
This is the actual directory rename.

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.

Complete copyright notices for web interface; change footer to link to them.

The original copyright notice found in the footer was not accurate as it
included only one of the many copyright holders in this project. This change
creates an "about" page, which currently contains just the copyright and
license information. It links to repository for additional potential copyright
holders not listed on the about page.

Unlisted contributors are mentioned in template comments.

Html links for Kallithea is fixed and we link to Conservancy.

Display of version information in the footer is improved.