Support LDAP directory using Dex

[neosab]

Support LDAP users in dispatch using CoreOS Dex https://github.com/coreos/dex

• [ ] Bug
• [X] Feature
• [ ] Enhancement

Detailed Description

Context

Possible Implementation

Complexity

• [ ] Low - Simple enhancement or bug fix, no architectural changes or refactoring
• [X] Medium - Change requires some thought, but is relatively isolated
• [ ] High - Significant architectural change or large refactor

Impact

• [X] Low - Annoyance, but does not impact business or functionality
• [ ] Medium - Issue can be worked around, but is causing pain
• [ ] High - Blocker

Your Environment

• Dispatch CLI version (or git commit):
• Dispatch Chart version (or image[s] tag):
• Operating System and version:
• Kubernetes version (and distribution):
• Etc (any other useful environmental information):