Integrate Okta for Authentication

[mraible]

Do not merge, this is just a PR to show how to integrate Okta into a Cloud Native PWA.

[lejinkr]

Getting the following error when I used

https://developer.okta.com/blog/2017/03/16/spring-boot-saml

error:
Caused by: java.lang.IllegalArgumentException: issuer cannot be empty
at org.springframework.util.Assert.hasText (Assert.java:276)
at com.okta.spring.oauth.discovery.OidcDiscoveryClient. (OidcDiscoveryClient.java:36)
at com.okta.spring.oauth.OktaPropertiesMappingEnvironmentPostProcessor.discoveryPropertiesSource (OktaPropertiesMappingEnvironmentPostProcessor.java:137)
at com.okta.spring.oauth.OktaPropertiesMappingEnvironmentPostProcessor.postProcessEnvironment (OktaPropertiesMappingEnvironmentPostProcessor.java:95)
at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEnvironmentPreparedEvent (ConfigFileApplicationListener.java:170)
at org.springframework.boot.context.config.ConfigFileApplicationListener.onApplicationEvent (ConfigFileApplicationListener.java:156)
at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener (SimpleApplicationEventMulticaster.java:172)
at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener (SimpleApplicationEventMulticaster.java:165)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent (SimpleApplicationEventMulticaster.java:139)
at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent (SimpleApplicationEventMulticaster.java:127)
at org.springframework.boot.context.event.EventPublishingRunListener.environmentPrepared (EventPublishingRunListener.java:73)
at org.springframework.boot.SpringApplicationRunListeners.environmentPrepared (SpringApplicationRunListeners.java:54)
at org.springframework.boot.SpringApplication.prepareEnvironment (SpringApplication.java:349)
at org.springframework.boot.SpringApplication.run (SpringApplication.java:317)

[mraible]

@lejinkr It seems kinda strange that you'd use the Okta Spring Boot Starter with SAML. Okta's Spring Boot Starter only works with OAuth/OIDC. See oktadeveloper/okta-spring-boot-saml-example for that blog post's example app.