schemas: fix bug in endpoint rule

[pamfilos]

Right now we have endpoints:

/jsonschemas/<name>/ /jsonschemas/<name>/<version> /jsonschemas/<name>/notifications /jsonschemas/<name>/<version>/notifications

We have errors raised in various cases, that the version is not passed e.g. /jsonschemas/<name>/blabla . in this case the blabla will be taken as a version and will raise error

We should eliminate these errors by creating a rule converter