Fix `docker/entrypoint.sh`

`docker/entrypoint.sh` was updated to fix errors that results in a
container that runs on a locally built Ferdi Server image.

Fixes that were made:

- shebang was changed to `#!/bin/sh` as the Node Alpine image does not
  have `bash`, therefore the container cannot start because of the error
  "/usr/local/bin/docker-entrypoint.sh: exec: line 8: /entrypoint.sh:
  not found";
- `if` condition was updated to make it more portable so it works with
  non-Bash shells;
- `su-exec` command was updated to remove the redundant `#!/bin/bash`
  from the end of the line as it was causing the error "Error: Cannot
  find module '/app/server.js#!/bin/bash'".

Additional code optimization changes:

- tabs were replaced with spaces;
- optimizations to avoid code duplication:
  - new variable `key_file` was added to hold the path to the Ferdi app
    key file;
  - the function `print_app_key_message` was added to print the
    informational message about the app key.

0 files changed, 0 insertions, 0 deletions