feat: update analytics so to meet IABv2 requirements

- https://iabtechlab.com/wp-content/uploads/2017/12/Podcast_Measurement_v2-Dec-20-2017.pdf
  - no IP address is ever stored on the server. Only aggregate data is stored in the dababase.
  - rolling 24-hour window
  - castopod does not do pre-load
  - IP Blacklisting https://github.com/client9/ipcat
  - user-agent Filtering https://github.com/opawg/user-agents
  - ignores 2 bytes range "Range: 0-1" (performed by official Apple iOS Podcast app)
  - in case of partial content, adds up all requests to check >1mn was downloaded
  - identifying Uniques is done with a combination of IP Address and User Agent
- add AMcharts
- add some graphs
- add regions to analytics
- add ipcat blacklist
- enhance useragents performances
- add filesize and header size in order to calculate 1mn downloads
- update publisher ID3 field
- update castopod icon
- add disclaimer and warning import form translation
- update docs/setup-development.md

closes #10