feat: bring back and adapt python bindings with rust core

* import python, try to adapt for rust

* add missing wrapper functions

* - try to write up how to build python bindings
- strike some unused functions from deltachat.h

* adjustments to make tox work

* try to run circle-ci with python build

* don't do docs

* running cargo test as well

* don't run cargo test anymore, that's done in other ci jobs

* also build docs

* don't run doxygen anymore

* subst C with Rust

* a try to get better wheels

Closes #41

python/doc/lapi.rst

@@ -0,0 +1,10 @@
+
+low level API reference
+===================================
+
+for full C-docs, defines and function checkout :doc:`capi`
+
+
+.. automodule:: deltachat.capi.lib
+    :members:
+