add requirements

Contentserver/requirements.txt

+appdirs==1.4.4
+apturl==0.5.2
+asgiref==3.3.1
+bcrypt==3.1.7
+blinker==1.4
+Brlapi==0.7.0
+certifi==2019.11.28
+chardet==3.0.4
+Click==7.0
+colorama==0.4.3
+command-not-found==0.3
+crypto==1.4.1
+cryptography==2.8
+cupshelpers==1.0
+dbus-python==1.2.16
+defer==1.0.6
+distlib==0.3.1
+distro==1.4.0
+distro-info===0.23ubuntu1
+Django==3.1.4
+django-cors-headers==3.7.0
+django-filter==2.4.0
+djangorestframework==3.12.2
+duplicity==0.8.12.0
+ecdsa==0.16.1
+entrypoints==0.3
+fasteners==0.14.1
+filelock==3.0.12
+future==0.18.2
+httpie==1.0.3
+httplib2==0.14.0
+idna==2.8
+keyring==18.0.1
+language-selector==0.1
+launchpadlib==1.10.13
+lazr.restfulclient==0.14.2
+lazr.uri==1.0.3
+lockfile==0.12.2
+louis==3.12.0
+macaroonbakery==1.3.1
+Mako==1.1.0
+Markdown==3.3.3
+MarkupSafe==1.1.0
+monotonic==1.5
+Naked==0.1.31
+netifaces==0.10.4
+oauthlib==3.1.0
+olefile==0.46
+paramiko==2.6.0
+pexpect==4.6.0
+Pillow==7.0.0
+protobuf==3.6.1
+pycairo==1.16.2
+pycrypto==2.6.1
+pycryptodome==3.9.9
+pycups==1.9.73
+Pygments==2.3.1
+PyGObject==3.36.0
+PyJWT==1.7.1
+pymacaroons==0.13.0
+PyNaCl==1.3.0
+PyQt5==5.15.1
+PyQt5-sip==12.8.1
+pyqt5-tools==5.15.1.1.7.4
+pyRFC3339==1.1
+python-apt==2.0.0+ubuntu0.20.4.3
+python-dateutil==2.7.3
+python-debian===0.1.36ubuntu1
+python-dotenv==0.14.0
+pytz==2019.3
+pyxdg==0.26
+PyYAML==5.3.1
+reportlab==3.5.34
+requests==2.22.0
+requests-unixsocket==0.2.0
+SecretStorage==2.3.1
+shellescape==3.8.1
+simplejson==3.16.0
+six==1.14.0
+sqlparse==0.4.1
+systemd-python==234
+ubuntu-advantage-tools==20.3
+ubuntu-drivers-common==0.0.0
+ufw==0.36
+unattended-upgrades==0.1
+urllib3==1.25.8
+usb-creator==0.3.7
+virtualenv==20.2.2
+wadllib==1.3.3
+xkit==0.0.0