GUACAMOLE-1746: Docker Allow usage of custom keystore and custom certificat

[tiborauer]

This PR takes over

• GUACAMOLE-1524: Importing LDAPS certificate into docker container #694
• GUACAMOLE-1746: Docker Allow usage of custom keystore and custom certificat #805

[necouchman]

@tiborauer Thank you for picking this up. Aside from the actual changes, there are a couple of logistical things that need to be addressed with this pull request:

• Please choose a single Jira item and tag it with that, don't try to do both. I'd recommend using 1746, as it is still open and 1524 is closed.
• All of your commit messages need to be tagged with the GUACAMOLE-1746: prefix.
• Your commit messages are going to need to be updated a bit to be more descriptive - the message should not be duplicated, and they should describe what the commit entails without just duplicating the content of the commit. See https://www.codelord.net/2015/03/16/bad-commit-messages-hall-of-shame/ for some hints on that :-).

[tiborauer]

Hi @necouchman,

• Re tagging: Can you elaborate on it a bit? Do I tag the PR with the JIRA item or the other way around?
• How do I edit the commit messages? Do you suggest recreating them?

[necouchman]

Hi @necouchman,

• Re tagging: Can you elaborate on it a bit? Do I tag the PR with the JIRA item or the other way around?

Both PR and Commit messages should be tagged with the Jira item. The PR you've done correctly, here, with the GUACMAOLE-1746: Docker allow usage of custom keystore and custom certificate.

However, the commit messages need this same GUACAMOLE-1746 prepended to the beginning of the message, for example:
GUACAMOLE-1746: Add the environment variables for custom keystore and certificate to the docker startup script.

You can look at other in-progress or merged PRs to see examples of this.

• How do I edit the commit messages? Do you suggest recreating them?

I find that the easiest way to do this is to do an interactive rebase (git rebase -i <COMMIT BEFORE YOUR COMMIT>), then, for each commit message you want to re-word, change the "pick" to "r" or "reword", edit the commit messages for each commit, and finally force-push the commits (git push -f). This will automatically update the PR, as well.