Configuration.md: make hyperlink relative

It was pointing to a specific branch, which isn't even the "main" dev
branch anymore.
Configuration.md: add more detail to pipeline conf

1) The suggested names for zerocloud middleware filters now are prefixed
with "zerocloud-", for disambiguation.
2) There are now detailed instructions for where the zerocloud filters
need to be placed in the "pipeline:main" configuration.
Configuration.md: add job chain config doc