Properly remap http port 80 mappings to https 443 when adding an ssl certificate

Rather than removing all port mappings, we simply remap port 80 mappings to 443. The previous behavior would remove custom port mappings for all applications and reset them on any certificate change, preventing automation from plugins such as letsencrypt. While this behavior doesn't matter for buildpack deploys - which only expose a single port on container port 5000 - Dockerfile deploys would frequently be affected by such a change, requiring a remapping of all custom ports.

This commit also standardizes on the method used to source the proxy functions

plugins/certs/subcommands/add

@@ -38,7 +38,6 @@ certs_set() {
   if is_file_import "$CRT_FILE" "$KEY_FILE"; then
     # importing from file
     true
-
   elif is_tar_import; then
     local CERTS_SET_TMP_WORK_DIR=$(mktemp -d "/tmp/dokku_certs_set.XXXX")
     pushd "$CERTS_SET_TMP_WORK_DIR" &> /dev/null
@@ -64,10 +63,8 @@ certs_set() {
     else
       local KEY_FILE=$KEY_FILE_SEARCH
     fi
-
   else
     dokku_log_fail "Tar archive containing server.crt and server.key expected on stdin"
-
   fi
 
   mkdir -p "$APP_SSL_PATH"