polish

- added 'discoverFunctionTypeFromFunctionalObject' method to FunctionTypeUtils
- added tests to reproduce and validate the issue

Don't assume function is a bean

Fixes #412

Resolves #395

* Fix spring-integration sample

* Added discoverFunctionTypeFromClass() method to FunctionTypeUtils

* A `FactoryBean` may produce a function instance as well.
Add a logic into `BeanFactoryAwareFunctionRegistry` to discover a function type from the `FactoryBean.getObjectType()`

Migrate away from deprecated Spring Boot configuration property
bean classes and methods.
Resolves #410

Fixed discovery of functions to ensure that even in cases where default function is found but it's type can not be determined such function is discarded. This effectively ensures that if the actual instance does not match the declared type such function is not treated as function.

Resolves #409

- Added initial support for communicating routing instructions via SpEL thru both message headers and application properties
- Added support for communication function definition via application properties
- Added additional tests and updated documentation

Resolves #408

Added FunctionRegistration for each Kotlin lambdas with the correct types
Resolve #364

- Update versions of aws-lambda-java-core to 1.2.0, aws-lambda-java-events to 2.2.6 and aws-java-sdk-s3 to 1.11.557

Resolves #373

Resolves #381

Add spring-cloud-function-kotlin to spring-cloud-function-dependencies.

This allows including the spring-cloud-function-kotlin dependency in a
new spring boot project without needing to explicitly specify the version.

This ultimately allows loading all JRE classes correctly, not only those
whose name are whitelisted.

Resolves #401

Resolves #403

- Added support for simple POJO functions
- Added additional utility methods

Fix Gradle build