This mediawiki package supports multiple instances, sometimes also
called Wiki Farms or Wiki Families, but you can use it for a single
instance just as well.

This works by running mw-createinstance <path>, where <path> is the
new desired location of your wiki(s) like

mw-createinstance /srv/my.host/wiki

Note that the parent directories must exist.

You also need to create an Apache config entry (if you use Apache for
serving mediawiki) like

DocumentRoot /srv/my.host/wiki
Alias /skins /usr/share/mediawiki/skins

<Directory "/srv/my.host/wiki">
  SetEnv MW_INSTALL_PATH "/srv/my.host/wiki"
  AllowOverride None
  Require all granted
</Directory>

(this example is for short URLs, e.g. ones w/o a "/wiki/" in the URL)