extmod/modtls: Move the native ssl module to tls.

The current `ssl` module has quite a few differences to the CPython
implementation.  This change moves the MicroPython variant to a new `tls`
module and provides a wrapper module for `ssl` (in micropython-lib).

Users who only rely on implemented comparible behavior can continue to use
`ssl`, while users that rely on non-compatible behavior should switch to
`tls`.  Then we can make the facade in `ssl` more strictly adhere to
CPython.

Signed-off-by: Felix Dörre <felix@dogcraft.de>

ports/unix/variants/coverage/manifest.py

@@ -1,3 +1,4 @@
 freeze_as_str("frzstr")
 freeze_as_mpy("frzmpy")
 freeze_mpy("$(MPY_DIR)/tests/frozen")
+require("ssl")

ports/unix/variants/manifest.py

@@ -1 +1,2 @@
 require("mip-cmdline")
+require("ssl")