Use Liquidjs instead of Liquid (#16743)

* Install liquidjs, uninstall liquid

* Comment a bunch of stuff out to get going

* Fix invalid includes

* Fix all includes (path => 'path')

* Get the homepage to render

* Do link-in-list kinda

* Revert "Fix all includes (path => 'path')"

This reverts commit d6fead646353aa5041d9229470a62a1d487456b9.

* Support non-dynamic partials

* Extract getTemplate helper

* Do remaining custom Liquid tags

* Fix some custom tag bugs

* Moar bugs

* Re-add link tag

* Cleaner diff

* Actually fix extended markdown tags

* Fully comment out version matchers

* Smaller diff

* Rely only on Liquid internals for conditionals

* Use new operators option in Liquid engine

* Fix link.js

* Don't need options

* Updoot to the right doot

* Fix some bugs

* Fix another bug

* Pass a test

* Fix the translate bits

* Adjust a test

* Fix another invalid Liquid bug

* Two more borked translations

* Found some more

* Don't need this change

* Revert "Don't need this change"

This reverts commit a916d619747f0492865a69c3e237c97c4d4e7fad.

* This should fix the broken links

* Missed one

* Revert "This should fix the broken links"

This reverts commit e6c2cc0d9055d958706260d57edbe293281c150e.

* Revert "Missed one"

This reverts commit bbe1f23baf16e020f6f7931589decb1afc75dfbd.

* Updoot liquidjs

lib/render-content/renderContent.js

@@ -21,7 +21,7 @@ const inlineTagRegex = new RegExp(`\n?(</?${inlineTagString}>?)\n?`, 'gm')
 
 // parse multiple times because some templates contain more templates. :]
 module.exports = async function renderContent (
-  template,
+  template = '',
   context = {},
   options = {}
 ) {