Simplify crate specs in config

[Jake-Shadle]

Currently, specifying a crate and a version range via a { name = "<krate_name>", version = "<version_req>", ... } is used in several locations in the config. This is "fine" but ends up being quite noisy in typical usage of wanting to configure a crate at all versions, the default if version is not specified, making the name = "" portion repetitive. Rather, it would be nicer to just collapse crate name + optional version requirements into a single string and just use a : or @ to separate the name from the version req if specified. This will tend to make larger configs with eg. lots of bans.deny much smaller and easier to read.