Switch to Hugo

This commit includes all the needed workarounds and most changes from the main branch for everything to work, like:

* removing empty lines in raw HTML that break output
* read .browserslistrc, CSS variables from disk instead of duplicating it
* using Hugo mounts
* using Hugo for the docs CSS/JS
* move ToC Sass code to a separate file while adapting it for Hugo

Thus, this patch makes our npm scripts faster since lint runs on one step and there's no separate docs assets processing.

site/assets/js/vendor/bs-custom-file-input.min.js

@@ -0,0 +1,7 @@
+/*!
+ * bsCustomFileInput v1.3.4 (https://github.com/Johann-S/bs-custom-file-input)
+ * Copyright 2018 - 2020 Johann-S <johann.servoire@gmail.com>
+ * Licensed under MIT (https://github.com/Johann-S/bs-custom-file-input/blob/master/LICENSE)
+ */
+!function(e,t){"object"==typeof exports&&"undefined"!=typeof module?module.exports=t():"function"==typeof define&&define.amd?define(t):(e=e||self).bsCustomFileInput=t()}(this,function(){"use strict";var s={CUSTOMFILE:'.custom-file input[type="file"]',CUSTOMFILELABEL:".custom-file-label",FORM:"form",INPUT:"input"},l=function(e){if(0<e.childNodes.length)for(var t=[].slice.call(e.childNodes),n=0;n<t.length;n++){var l=t[n];if(3!==l.nodeType)return l}return e},u=function(e){var t=e.bsCustomFileInput.defaultText,n=e.parentNode.querySelector(s.CUSTOMFILELABEL);n&&(l(n).textContent=t)},n=!!window.File,r=function(e){if(e.hasAttribute("multiple")&&n)return[].slice.call(e.files).map(function(e){return e.name}).join(", ");if(-1===e.value.indexOf("fakepath"))return e.value;var t=e.value.split("\\");return t[t.length-1]};function d(){var e=this.parentNode.querySelector(s.CUSTOMFILELABEL);if(e){var t=l(e),n=r(this);n.length?t.textContent=n:u(this)}}function v(){for(var e=[].slice.call(this.querySelectorAll(s.INPUT)).filter(function(e){return!!e.bsCustomFileInput}),t=0,n=e.length;t<n;t++)u(e[t])}var p="bsCustomFileInput",m="reset",h="change";return{init:function(e,t){void 0===e&&(e=s.CUSTOMFILE),void 0===t&&(t=s.FORM);for(var n,l,r=[].slice.call(document.querySelectorAll(e)),i=[].slice.call(document.querySelectorAll(t)),o=0,u=r.length;o<u;o++){var c=r[o];Object.defineProperty(c,p,{value:{defaultText:(n=void 0,n="",(l=c.parentNode.querySelector(s.CUSTOMFILELABEL))&&(n=l.textContent),n)},writable:!0}),d.call(c),c.addEventListener(h,d)}for(var f=0,a=i.length;f<a;f++)i[f].addEventListener(m,v),Object.defineProperty(i[f],p,{value:!0,writable:!0})},destroy:function(){for(var e=[].slice.call(document.querySelectorAll(s.FORM)).filter(function(e){return!!e.bsCustomFileInput}),t=[].slice.call(document.querySelectorAll(s.INPUT)).filter(function(e){return!!e.bsCustomFileInput}),n=0,l=t.length;n<l;n++){var r=t[n];u(r),r[p]=void 0,r.removeEventListener(h,d)}for(var i=0,o=e.length;i<o;i++)e[i].removeEventListener(m,v),e[i][p]=void 0}}});
+//# sourceMappingURL=bs-custom-file-input.min.js.map