Slim down dependencies

* Make jinja2 an optional dependency and csrgen an optional plugin
* Make otptoken_yubikey an optional plugin

Signed-off-by: Christian Heimes <cheimes@redhat.com>
Reviewed-By: Martin Basti <mbasti@redhat.com>

tox.ini

@@ -13,7 +13,7 @@ changedir={envdir}
 setenv=
     HOME={envtmpdir}
 deps=
-    ipaclient
+    ipaclient[csrgen]
     ipatests
 commands=
     {envbindir}/ipa --help
@@ -22,7 +22,7 @@ commands=
 [testenv:pylint2]
 basepython=python2.7
 deps=
-    ipaclient[otptoken_yubikey]
+    ipaclient[csrgen,otptoken_yubikey]
     pylint
 commands=
     {envpython} -m pylint \