*: update go-oidc to remove dependency on capnslog

This change updates the vendored go-oidc package to remove the
dependency on capnslog. It also pulls in a few other minor changes
as part of that package's development.

refresh token rotation

Update refresh token flow to revoke old refresh token and generates a new one.

Fixes #519

*: pin version of openldap container

Upstream changes to the osixia/openldap broke our LDAP intergraiton
tests. For now pin the version of oxisia/openldap. Long term rewrite
the tests do they don't depend on the container's file system,
possibly when addressing #477.

Closes #554

documentation: fix getting-started

documentation: fix typos in getting-started

| Typo           | Fix            |
| -------------- | -------------- |
| a an api       | an api         |
| adminsitrative | administrative |
| attemping      | attempting     |

[skip ci]
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

The discovery URL has changed and now ends with /dex. As the scripts
were updated in #525, the documentation was not.

Broken since #521.

[skip ci]
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>

connector: add azure connector

Add emailCiam setting to OIDC Connector for supporting an ID token
that does not contain the email claim.

*: update examples to hold valid client secrets for no-db mode

connector: add uaa connector

server: when registering a user, set user name if OIDC identity contains one

This commit adds support for dex to authenticate users from a
CloudFoundry User Account and Authentication (UAA) Server.

Fixes: #538

Fix typo in dexctl parameter

When automatically registering a user from an IP that provides
a `DisplayName`, set it on the created user so that JWT we create
contain a meaningful `name` field.

user api: accept bearer tokens with multiple audiences

*: cleanup containers generated during tests to avoid deploy conflicts

*: fix path to email config in dockerfile

*: try to fix travis deployments by adding script with no arguments

Fix standup-db.sh

Allow dex to work at non base url

connector: fix path that connectors listen on

When Dex uses a non-root issuer URL, it current assumes that all
path prefixes will be trimmed by an upstream proxy (e.g. nginx).
This means that all paths rendered in HTML will be absolute to the
prefix, but the handlers still listen at the root.

Connectors are currently the only component that registers at a
non-root URL. Make this conform with the rest of Dex by having the
server determine the path the connector listens as rather than the
connector itself.

backend: add absolute path to template links

fixes: #502

Add a new template function called `absPath` that converts relative
paths to absolute paths based on the issuerURL. The template function
can be used in templates like:
````html
<a href="{{ .MyRelativePath | absPath }}">
````