server: add expires_in field to the response of token endpoint

documentation: multiple fixes in examples README

* In a9dce1c1, the defaults are set to the `.example` paths, except for `emailer.json` which is instead committed into the git repository. So there's no need to duplicate those file in order to start dex-worker.
* The default value for discovery is moved from `/` to `/dex` in #521
* Typo in `client-secret` value.

ClientCredentials flow in basic User operations (createUser, getUser, resendInvitationMail)

Fixes #528

Update go-oidc for hmac changes

server: fix registration redirect for non-root URLs

server: fix the path registration for user APIs at non-root URLs

*: 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