THe "null" and "null@l2tp" methods are considered equivalent and always
added and removed together when the method list is "configurable".
"null@l2tp" is added before "null", so it is preferred when the peer
supports both.
- CGI script and index.html are moved from gluon-web to
gluon-config-mode-core, the script is renamed to 'config'
- gluon-web and gluon-web-model base views and i18n files are symlinked
into the new path
- gluon-web-theme is renamed to gluon-config-mode-theme and installs
directly into the new path
- all gluon-web-* models, controllers and views are moved into the new
path
