897 support heroku redis tls connection

[Workhqd]

This pr is to solve the issue 897 support heroku redis tls connection.
This branch has been update based on the new version. I have rebase rebase this branch on top of master.
I have done two tests.

First test: test the job could be enqueue or not

Second test: open the democracylab website, login the test account, and then send the email to the volunteer. If the job is enqueued correctly, the rqworker could handle the job. And finally, you could see the email in the rqworker windows rather than the windows you ran python manage.py runserver.

First test's steps:

1. sudo apt install redis-server
2. sudo apt install openssl
3. sudo mkdir /etc/redis/ssl
4. Generate the private key and self-signed certificate using the following command:
   sudo openssl req -x509 -newkey rsa:4096 -keyout /etc/redis/ssl/redis.key -out /etc/redis/ssl/redis.crt -days 365 -nodes
5. Edit the Redis configuration file: sudo nano /etc/redis/redis.conf
   Add: port 6379
   tls-port 6380
   tls-cert-file /etc/redis/ssl/redis.crt
   tls-key-file /etc/redis/ssl/redis.key
   tls-ca-cert-file /etc/redis/ssl/redis.crt
6. Add two environment variables in the
   export REDIS_ENABLED='True'
   export REDIS_URL='rediss://localhost:6380/0?ssl_cert_reqs=none&ssl_ca_certs=/etc/redis/ssl/redis.crt'
7. write a test.py( I have deleted it from this branch)
8. restart the vm
   open a window and run:
   source ~/Desktop/democracylab_environment_variables.sh
   source ~/git/virtualenv/bin/activate
   sudo -E redis-server --tls-port 6380 --tls-cert-file /etc/redis/ssl/redis.crt --tls-key-file /etc/redis/ssl/redis.key --tls-ca-cert-file /etc/redis/ssl/redis.crt --tls-auth-clients no --tls-replication yes
   open another window and run:
   source ~/Desktop/democracylab_environment_variables.sh
   source ~/git/virtualenv/bin/activate
   cd ~/git/CivicTechExchange
   python manage.py rqworker
   open third window and run:
   source ~/Desktop/democracylab_environment_variables.sh
   source ~/git/virtualenv/bin/activate
   python manage.py test

Second test's steps:
1-5 steps in first test's step
6. Add an environment variable:
export REDIS_ENABLED='True'
7. restart the vm
open a window and run:
source ~/Desktop/democracylab_environment_variables.sh
source ~/git/virtualenv/bin/activate
sudo -E redis-server --tls-port 6380 --tls-cert-file /etc/redis/ssl/redis.crt --tls-key-file /etc/redis/ssl/redis.key --tls-ca-cert-file /etc/redis/ssl/redis.crt --tls-auth-clients no --tls-replication yes
open another window and run:
source ~/Desktop/democracylab_environment_variables.sh
source ~/git/virtualenv/bin/activate
cd ~/git/CivicTechExchange
python manage.py rqworker
open third window and run:
source ~/Desktop/democracylab_environment_variables.sh
source ~/git/virtualenv/bin/activate
python manage.py runserver
8. open the website and send an email(contact the volunteer)