We need to wait for Bullseye before really enabling it.

All topics except "installation", "management", "contributing" and
"release notes" are moved to a new "administration" branch.

This reduces the number of top-level topics down to five.

See https://github.com/silicann/kien/issues/1

Somehow it got lost in the documentation of the source-based deployment.

Previously just the existence of the virtualenv was verified.

These operations are natively supported by makefilet now (with a hyphen
instead of the underscore).
We already use the new names everywhere.

This matrix bot can be used for managing users and content in a
grouprise instance.

With the new `--print-only` setting it is possible to register an
account for the new "matrix-commander" feature.

Previously appending only worked for tuples.
Now it works for both lists and tuples.

This should help the local admin to detect misspellings or outdated
settings.

The new `scripts` setting allows to configure site-local javascript
code:

  scripts:
    - path: /custom.js
      load: defer
    - content: 'alert("hello");'

This may partly remove the need for local overrides via
`core/_head.html`.

Closes: #688

The new `stylesheets` setting allows to configure site-local CSS styles:

  stylesheets:
    - path: /custom.css
    - path: /print.css
      media: print

This may partly remove the need for local overrides via
`core/_head.html`.

See: #688

This is mainly useful for testing.

Previously relative paths would be evaluated at runtime.
Now the paths are evaluated during configuration and stored as absolute
paths.

Previously accessing a non-existing dictionary returned an item, but its
changes were not propagated to the parent dictionary.

Previously the error message was misleading.

Preparation for tests.