Implementation to add/remove filters along with package/package-group filters

- added a common fn `go_to_filter_page` as its required for all methods related to filters
- Implemented fn `add_filter` for adding inclusion/exclusion type filters and based on given content-type(errata, package o package-group)
- added fn `remove_filter` to remove one or multiple filters
- implemented support for adding packages to package type filter with different version types, the   implementation includes following functions:
   - fn `select_package_version_value` to update version value based on version type
   - fn `add_packages_to_filter` to add packages for inclusion/exclusion
- Added support to add/remove package groups from selected package-group type filter
- Added following 3 tests:
    - `test_remove_filter`
    - `test_create_package_filter`
    - `test_create_package_group_filter`