upgrade smarty to v5.4.0

[mdaniels5757]

Breaking this out per #969.

[stwalkerster]

I've not spent too much time testing this properly yet, but I am seeing a few things.

It looks like the fix we did for the implode modifier in #965 hasn't worked as Smarty still has an implode modifier built-in (and throwing deprecation warnings). I've bodged it on team/user.tpl locally, but I'm not sure if this is all cases we need to fix:

-  <li>{'</li><li>'|implode:$infoContent}</li>
+  <li>{$infoContent|join:'</li><li>'}</li>

There's also a lot of deprecation warnings being thrown by TemplateOutput::setUpSmarty, as the call to addPluginsDir is also deprecated. The number of deprecation warnings this is throwing on every single page load isn't great. I think something like this is working, but I don't know for sure yet. There's probably a much better way to do it than this:

        $pluginsDir = $this->getSiteConfiguration()->getFilePath() . '/smarty-plugins';
//        $this->smarty->addPluginsDir($pluginsDir);

        /** @var DirectoryIterator $file */
        foreach (new DirectoryIterator($pluginsDir) as $file) {
            if ($file->isDot()) {
                continue;
            }

            if ($file->getExtension() != 'php') {
                continue;
            }

            require_once $file->getPathname();

            list($type, $name) = explode('.', $file->getBasename('.php'), 2);

            switch ($type) {
                case 'modifier':
                    $this->smarty->registerPlugin(Smarty::PLUGIN_MODIFIER, $name, 'smarty_modifier_' . $name);
                    break;
                case 'function':
                    $this->smarty->registerPlugin(Smarty::PLUGIN_FUNCTION, $name, 'smarty_function_' . $name);
                    break;
            }
        }

I've also looked at the ban list on /internal.php/bans, and that's actually properly broken too.

Exception 0: Smarty\CompilerException

Syntax error in template "file:bans/list.tpl" on line 39 "{if $ban->getDuration() < time() && $ban->getDuration() !== null}<span class="badge badge-warning">Expired</span>{/if}" unknown modifier 'time'

#0 ./vendor/smarty/smarty/src/Compile/ModifierCompiler.php(74): Smarty\Compiler\Template->trigger_template_error('unknown modifie...', 39, true)
#1 ./vendor/smarty/smarty/src/Compiler/Template.php(498): Smarty\Compile\ModifierCompiler->compile(Array, Object(Smarty\Compiler\Template), Array)
#2 ./vendor/smarty/smarty/src/Compiler/Template.php(1383): Smarty\Compiler\Template->compileModifier(Array, NULL)
#3 ./vendor/smarty/smarty/src/Parser/TemplateParser.php(2726): Smarty\Compiler\Template->compileModifierInExpression('time', Array)
#4 ./vendor/smarty/smarty/src/Parser/TemplateParser.php(2902): Smarty\Parser\TemplateParser->yy_r149()
#5 ./vendor/smarty/smarty/src/Parser/TemplateParser.php(2997): Smarty\Parser\TemplateParser->yy_reduce(149)
#6 ./vendor/smarty/smarty/src/Compiler/Template.php(1269): Smarty\Parser\TemplateParser->doParse(53, ' && ')
#7 ./vendor/smarty/smarty/src/Compiler/Template.php(437): Smarty\Compiler\Template->doCompile('

I've not spent a decent amount of time testing this yet, so there may be more things to be uncovered.