Make uncomplicated modules private (#7528)

* Create _internal package for Certbot's non-public modules

* Move account.py to _internal

* Move auth_handler.py to _internal

* Move cert_manager.py to _internal

* Move client.py to _internal

* Move error_handler.py to _internal

* Move lock.py to _internal

* Move main.py to _internal

* Move notify.py to _internal

* Move ocsp.py to _internal

* Move renewal.py to _internal

* Move reporter.py to _internal

* Move storage.py to _internal

* Move updater.py to _internal

* update apache and nginx oldest requirements

* Keep the lock file as certbot.lock

* nginx oldest tests still need to rely on newer certbot

* python doesn't have good dependency resolution, so specify the transitive dependency

* update required minimum versions in nginx setup.py

certbot-nginx/local-oldest-requirements.txt

@@ -1,3 +1,3 @@
 # Remember to update setup.py to match the package versions below.
-acme[dev]==0.29.0
-certbot[dev]==0.36.0
+-e acme[dev]
+-e .[dev]

certbot-nginx/setup.py

@@ -9,8 +9,8 @@ version = '1.0.0.dev0'
 # Remember to update local-oldest-requirements.txt when changing the minimum
 # acme/certbot version.
 install_requires = [
-    'acme>=0.29.0',
-    'certbot>=0.35.0',
+    'acme>=1.0.0.dev0',
+    'certbot>=1.0.0.dev0',
     'mock',
     'PyOpenSSL',
     'pyparsing>=1.5.5',  # Python3 support; perhaps unnecessary?