Function provider SPI, fix GraalVM image

Improvements:

• Add missing SCM data to generated pom.xml 3c1d2f5
• SPI providers for function implementations #166
• add install target for Makefile 0816a6c

GraalVM service implementation:

• Fix reflection error that broke GraalVM image b196f56
• Update GraalVM version to latest b4b2951