Fixes based off KB's super kind review.

-------
* Remove unnecessary packages from dockerfile for the demo-connect proxy.
* Rename an environment variable that mentioned Status.im in what is now a generic connector.
* Fixed a spelling mistake.

Dockerfile

@@ -6,8 +6,7 @@ RUN useradd _gunicorn --no-create-home --user-group
 RUN apt-get update && \
     apt-get install -y -q \
         gcc libssl-dev \
-        curl git-core libpq-dev \
-        gunicorn3 default-mysql-client
+        curl gunicorn3
 
 WORKDIR /app
 COPY pyproject.toml poetry.lock /app/

bin/boot_server_in_docker

@@ -7,7 +7,7 @@ function error_handler() {
 trap 'error_handler ${LINENO} $?' ERR
 set -o errtrace -o errexit -o nounset -o pipefail
 
-port="${CONNECTOR_PROXY_STATUS_IM_PORT:-}"
+port="${CONNECTOR_PROXY_PORT:-}"
 if [[ -z "$port" ]]; then
   port=7004
 fi