Fix strict standard warnings in dropdowns for PHP <=5.6

PHP 5.6 and below throw a strict standards warning at the changed lines.
An intermediate variable is introduced to avoid this warning.

PHP 7+ changes the severity of this warning to E_NOTICE which is
suppressed by DokuWiki.

This error was introduced in #1778

When an svg has a fill attribute directly on the path, we need more
specifity to override it.

Translation update (no)

ran svgo over all the admin svg files to strip all unneeded cruft.

Translation update (ja)

Translation update (zh)

similar to what is possible for plugins, templates can now autoload
namespaced classes, too. the namespace is
dokuwiki\template\<templatename>

This makes it more flexible to use on the expense of needing one echo
more.

$pagelog->getRevisions(-1, 1) cannot be passed to array_pop() as the
parameter $array expects a reference.

remove fullpath() call in pageinfo

 added rev number to most recent link in old revisions page

All script tags are now surrounded by conditional comments to tell
Internet Explorer 8 and lower to not even bother trying to load the
JavaScript.

* jqsplit:
  Restore smoothness.css using update.sh
  allow selecting the preferred CDN and add event
  load jquery via https always
  split off jquery from other JS and add CDN option #1766
  use external version file for jquery updates
  removed jQuery.browser calls
  replace deprecated bind() calls
  replace deprecated delegate() calls
  fixed radio options in media manager for new jQ-UI
  jQuery Updates

fix problems with header that look falsy. fixes #1770

Handle delayed writes gracefully

updated SimplePie and moved to composer based install. #1800

Admin Page refactoring

* use inline-block instead of flexbox
* fix RTL alignments

This reverts commit b8b60fdb.

The images are now to be seen as deprecated but will remain for a little
longer. They will be released in the future.

now comments and line breaks between tags are removed

Fix broken JS in xhtml

Add height: auto to video element css

This allows plugins to easily render a <tfoot> element in a table, even
though it's not used in standard table syntax it makes sense to have it
available.