Possibility to pass location of the config and credentials file

[ahochsteger]

Currently the location of the config and credentials file is hard-coded to certain locations - see: https://github.com/danielgtaylor/openapi-cli-generator/blob/5c2358b319179c5095a868c73f844c6a5d6ee736/cli/credentials.go#L228 https://github.com/danielgtaylor/openapi-cli-generator/blob/5c2358b319179c5095a868c73f844c6a5d6ee736/cli/cli.go#L159 This would allow to use dynamically created config and credentials files to prevent race conditions, if the CLI is used in parallel for different situations.