Use proper passwords for Mysql, set password for Judgehost user

[maartenberg]

• Add vault.yml with encrypted secrets
• Use this file via vars_files
• Do dirty SQL command to ensure that the judgehost user is created
• Use secrets from vault.yml to set judgehost, mysql passwords
• Add deploy script that pulls password from a file
• Ignore this password file
• ???
• Profit

Still needs to be tested by setting up a new server with it