Multi certificate support

[rupertbg]

• Fixed recursive .gitignore
• Updated Access Control doc
• Move CertificateOptions to it's own type
• Added SSH permissions generator function
• Added support for multiple certificates in CLI filesystem
• A certificate is now generated per jumphost in Auth Lambda response

[rupertbg]

Worth nothing that ci/expected-output-jumpbox-sshconf.txt has to have two trailing new lines..