doc/website: migration to docosaurus v2 (#1384)

* WIP - migrating entgo.io to docosaurus v2

* organizing pages a bit to be better suited for v2 site structure

* doc/website: finish migration to docusaurus v2

Co-authored-by: Rotem Tamir <rotemtamir@gmail.com>

doc/website/src/theme/prism-include-languages.js

@@ -0,0 +1,37 @@
+
+/**
+ * Copyright 2019-present Facebook Inc. All rights reserved.
+ *
+ * This source code is licensed under the Apache 2.0 license found
+ * in the LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+
+export default function(Prism) {
+  Prism.languages.gotemplate = {
+    'comment': [
+      {
+        pattern: /(^|[^\\])\/\*[\s\S]*?(?:\*\/|$)/,
+        lookbehind: true,
+        greedy: true
+      },
+      {
+        pattern: /(^|[^\\:])\/\/.*/,
+        lookbehind: true,
+        greedy: true
+      },
+      /{{\/\*[\s\S]*\*\/}}/
+    ],
+    'string': {
+      pattern: /(["'])(?:\\(?:\r\n|[\s\S])|(?!\1)[^\\\r\n])*\1/,
+      greedy: true
+    },
+    'boolean': /\b(?:_|iota|nil|true|false)\b/,
+    'number': /(?:\b0x[a-f\d]+|(?:\b\d+(?:\.\d*)?|\B\.\d+)(?:e[-+]?\d+)?)i?/i,
+    'operator': /[*\/%^!=]=?|\+[=+]?|-[=-]?|\|[=|]?|&(?:=|&|\^=?)?|>(?:>=?|=)?|<(?:<=?|=|-)?|:=|\.\.\./,
+    'builtin': /\b(?:bool|byte|complex(?:64|128)|error|float(?:32|64)|rune|string|u?int(?:8|16|32|64)?|uintptr|append|cap|close|complex|copy|delete|imag|len|make|new|panic|print(?:ln)?|real|recover)\b/,
+    'keyword': /\b(?:break|default|func|interface|select|case|map|struct|chan|else|goto|package|switch|const|fallthrough|if|range|type|continue|for|import|return|var|go|defer|bool|byte|complex64|complex128|float32|float64|int8|int16|int32|int64|string|uint8|uint16|uint32|uint64|int|uint|uintptr|rune|with|define|block|end)\b/,
+  };
+}