feat(black-duck): Support external IDs using the "long_tail" namespace

The `externalIds` for the `long_tail` namespace are simply repository
URLs using e.g. the `git` protocol. The forge `Forge.LONG_TAIL` defines
the `/` as the separator. When the `integration-bdio` library creates
the query string, it accidentally replaces the double slash with a
single one, e.g. `git:/` instead of `git://`. As result, any request
returns an empty result.

Work around that by simply using the `:` as separator, because no double
colon should occur in any repository URL. So, when splitting and
re-joining the string using `:` as separator, that issue does not happen
anymore.

Signed-off-by: Frank Viernau <[email protected]>

Author: fviernau