Migrate to Docusaurus (#329)

* docs: initial migration to docusaurus

* website: add custom font, update blurbs and icons

* website: update splash

* root: update links to docs

* flows: use .pbflow extension so docusaurus doesn't mangle the files

* e2e: workaround prospector

* Squashed commit of the following:

commit 1248585dca
Author: Jens Langhammer <jens.langhammer@beryju.org>
Date:   Sun Nov 15 20:46:53 2020 +0100

    e2e: attempt to fix prospector error again

commit 1319c480c4
Author: Jens Langhammer <jens.langhammer@beryju.org>
Date:   Sun Nov 15 20:41:35 2020 +0100

    ci: install previous python version for upgrade testing

* web: update accent colours and format

* website: format markdown files

* website: fix colours for text

* website: switch to temporary accent colour to improve readability

* flows: fix path for TestTransferDocs

* flows: fix formatting of tests

website/docs/providers/saml.md

@@ -0,0 +1,13 @@
+---
+title: SAML Provider
+---
+
+This provider allows you to integrate enterprise software using the SAML2 Protocol. It supports signed requests and uses [Property Mappings](../property-mappings/index.md#saml-property-mapping) to determine which fields are exposed and what values they return. This makes it possible to expose vendor-specific fields.
+Default fields are exposed through auto-generated Property Mappings, which are prefixed with "Autogenerated".
+
+| Endpoint               | URL                                                          |
+| ---------------------- | ------------------------------------------------------------ |
+| SSO (Redirect binding) | `/application/saml/<application slug>/sso/binding/redirect/` |
+| SSO (POST binding)     | `/application/saml/<application slug>/sso/binding/post/`     |
+| IdP-initiated login    | `/application/saml/<application slug>/sso/binding/init/`     |
+| Metadata Download      | `/application/saml/<application slug>/metadata/`             |