Add a configuration option for download retry attempts

**Is your feature request related to a problem? Please describe.**
I'm behind a corporate proxy and for whatever reason every second attempt of downloading NVD data fails with a "Connection Reset" error and thus with the current version of DependencyCheck I'm not able to complete all the necessary downloads successfully.

**Describe the solution you'd like**
My current solution is hacky. I simply added an endless loop to `HttpResourceConnection.fetch` which keeps re-trying the download until it eventually succeeds. This way I finally managed to get a successful build with the `dependency-check-maven` plugin. A more elegant solution (and the one I'm hoping for) is, add a configuration option where one can specify how many retrys might be appropriate for their situation. In my case I never needed more than 3 retries until a file got downloaded successfully.

**Additional context**
_Possible configuration option_
```XML

org.owasp
dependency-check-maven
6.2.1-SNAPSHOT

10




update-only




```