Package cve-manager: Information

- Names of used programming languages are collected during the import stage from
  the GitHub and SourceForge platforms to improve the mapping of CPE products to
  packages;
- New auxiliary utilities: 1) "find-controversial-urls", used to display matches
  between packages and CPEs, where both the package and CPE have links to one of
  the popular software platforms, but none of these links are refer to a same
  project, and 2) "join-gathered-info", used to join existing text files which
  contain gathered info -- both of them can be found in the source files;
- All ALT errata issues are taked into account even for packages that are not
  mapped;
- Lots of minor improvements.

- Fixed build.

- No more redundant information when querying a list of issues for packages
  that have user-specified versions;
- A guest user can run the "cve-issues --full_package_names ..." command.