* add exclusion api, fixes#311
add new apis: `POST crawls/{crawl_id}/exclusion?regex=...` and `DELETE crawls/{crawl_id}/exclusion?regex=...` which will:
- create new config with add 'regex' as exclusion (deleting or making inactive previous config) OR remove as exclusion.
- update crawl to point to new config
- update statefulset to point to new config, causing crawler pods to restart
- filter out urls matching 'regex' from both queue and seen list (currently a bit slow) (when adding only)
- return 400 if exclusion already existing when adding, or doesn't exist when removing
- api reads redis list in reverse to match how exclusion queue is used
793611e5bb