README.md: Update with links from seL4 docsite

https://docs.sel4.systems/projects/sel4/ contains several links that are
helpful to link to from the seL4 readme.

Signed-off-by: Kent McLeod <Kent.Mcleod@data61.csiro.au>

README.md

@@ -4,10 +4,10 @@
      SPDX-License-Identifier: GPL-2.0-only
 -->
 
-The seL4 Repository
-===================
+The seL4 microkernel
+====================
 
-This repository contains the source code of seL4 microkernel.
+This project contains the source code of seL4 microkernel.
 
 For details about the seL4 microkernel, including details about its formal
 correctness proof, please see the [`sel4.systems`][1] website and associated
@@ -22,18 +22,47 @@ on [how to contribute][3].
 This repository is usually not used in isolation, but as part of the build
 system in a larger project.
 
+
   [1]: http://sel4.systems/
-  [2]: http://sel4.systems/Info/FAQ/
-  [3]: http://sel4.systems/Community/Contributing/
+  [2]: https://docs.sel4.systems/projects/sel4/frequently-asked-questions
+  [3]: https://docs.sel4.systems/processes/contributing.html
   [4]: https://zenodo.org/badge/DOI/10.5281/zenodo.591727.svg
   [5]: https://sel4.systems/Info/Docs/seL4-manual-latest.pdf
-  [6]: http://sel4.systems/Info/GettingStarted/
+  [6]: https://docs.sel4.systems/GettingStarted
+  [7]: https://docs.sel4.systems/releases/sel4
+  [8]: https://docs.sel4.systems/projects/sel4/api-doc.html
+
+seL4 Basics
+---------------
+
+- [Tutorials](https://docs.sel4.systems/Tutorials)
+- [Documentation](https://docs.sel4.systems/projects/sel4/documentation)
+- [seL4 libraries](https://docs.sel4.systems/projects/user_libs)
+- [seL4Test](https://docs.sel4.systems/project/sel4test)
+- [Debugging guide](https://docs.sel4.systems/projects/sel4-tutorials/debugging-guide)
+- [Benchmarking guide](https://docs.sel4.systems/projects/sel4-tutorials/benchmarking-guide.html)
+- [Virtualization on seL4](https://docs.sel4.systems/projects/virtualization/)
+- [Host Build Dependencies](https://docs.sel4.systems/projects/buildsystem/host-dependencies.html)
+- [Porting seL4](https://docs.sel4.systems/projects/sel4/porting)
+
+
+Community
+---------
+
+- Mailing lists
+  - [seL4 Announce](https://sel4.systems/lists/listinfo/announce)
+  - [seL4 Devel](https://sel4.systems/lists/listinfo/devel)
+- [Suggested projects](/SuggestedProjects)
+- [CommunityProjects](/CommunityProjects)
+
 
 Manual
 ------
 
 A hosted version of the [manual](manual/) for the most recent release can be found [here][5].
 
+A web version of the API can be found [here][8]
+
 Repository Overview
 -------------------
 
@@ -47,3 +76,16 @@ Build Instructions
 ------------------
 
 See the seL4 website for [build instructions][6].
+
+
+Status
+------
+
+A list of releases and current project status can be found under [seL4 releases][7].
+
+- [Roadmap](https://docs.sel4.systems/projects/roadmap): new features in development
+- [Hardware Support](https://docs.sel4.systems/Hardware): information about hardware platform ports
+- [Kernel Features]((https://docs.sel4.systems/projects/sel4/status)): information about available kernel features
+- [Userland Components and Drivers](https://docs.sel4.systems/projects/available-user-components.html): available device drivers and
+      userland components
+