storage/kubernetes: Removing Kubernetes TPR support

Third Party Resources (TPR) have been removed from Kubernetes for
roughly 2 years.  This commit removes the support dex had for them.

Documentation has been updated to reflect this and to instruct users
on how to migrate from TPR-powered dex environment to a Custom Resource
Defintion (CRD) based one that dex > v2.17 will support

bump deps for http2 issues

https://github.com/grpc/grpc-go/releases/tag/v1.23.0

https://groups.google.com/forum/#!topic/golang-nuts/fCQWxqxP8aA

Signed-off-by: Stephan Renatus <srenatus@chef.io>

Signed-off-by: Stephan Renatus <srenatus@chef.io>

Add examples for recent additions to oauth2 configuration options

Add reflection to gRPC API (configurable)

Add option to always display connector selection even if there's only one

Allow arbitrary data to be passed to templates

Add tests for some callback handler error conditions

Adjusting Makefile so that `golint` will compile

Return HTTP 400 for invalid state parameter

update all deps

Signed-off-by: Stephan Renatus <srenatus@chef.io>

Signed-off-by: Stephan Renatus <srenatus@chef.io>

Signed-off-by: Stephan Renatus <srenatus@chef.io>

server/api: fix logging in VerifyPassword

Before:

    msg="api: password check failed : %vcrypto/bcrypt: hashedPassword is not the hash of the given password"

After:

    msg="api: password check failed : crypto/bcrypt: hashedPassword is not the hash of the given password"
Signed-off-by: Stephan Renatus <srenatus@chef.io>

*: fix some lint issues

Mostly gathered these using golangci-lint's deadcode and ineffassign
linters.
Signed-off-by: Stephan Renatus <srenatus@chef.io>

Return config validation errors in one go

Doc/storage.md: fix mysql sample query

connector/gitlab: implement useLoginAsID as in GitHub connector

microsoft: option for group UUIDs instead of name and group whitelist

add connector_id to example app

Now, we'll return a standard error, and have the caller act upon this
being an instance of authErr.

Also changes the storage.AuthRequest return to a pointer, and returns
nil in error cases.
Signed-off-by: Stephan Renatus <srenatus@chef.io>

Signed-off-by: Stephan Renatus <srenatus@chef.io>

As a piece of "living documentation" for #1481.
Signed-off-by: Stephan Renatus <srenatus@chef.io>