AIP#61: AdEx V5: adview-manager: AIP#31 Targeting changes

[elpiel]

Part of #296

Required for #312

TODOs:

AIP#31 Targeting changes

• Add defaults (maybe as static/constants instead of setting them up as in the JS impl) https://github.com/AdExNetwork/adex-adview-manager/blob/cbb0217d80/src/main.ts#L16-L20
• Add tests Infinity Behaviour + AdView Manager Tests #566
• Compare output of JS impl
• Check Targeting Input
• Default empty string for Input::navigator_language See: https://github.com/AdExNetwork/adex-validator-stack-rust/blob/7fd8a4b9c39ba9cbb57367c7a90f07823af7643d/adview-manager/src/lib.rs#L329-L330
• Double-check if this .expect() is reasonable. See:
  https://github.com/AdExNetwork/adex-validator-stack-rust/blob/7fd8a4b9c39ba9cbb57367c7a90f07823af7643d/adview-manager/src/lib.rs#L358-L368 Infinity Behaviour + AdView Manager Tests #566
• Fix / Check .unwrap() and what should happen if we don't find the ValidatorDesc. See:
  https://github.com/AdExNetwork/adex-validator-stack-rust/blob/7fd8a4b9c39ba9cbb57367c7a90f07823af7643d/adview-manager/src/lib.rs#L548-L558 @simzzz
• Apply Infinity and check how it's Serialized in JSON. Make sure the behaviour is the same!
  https://github.com/AdExNetwork/adex-adview-manager/blob/cbb0217d80f35b8febe56fd3dde10cdfd50ca5d7/src/main.ts#L141-L143 Infinity Behaviour + AdView Manager Tests #566

AIP#61 V5

• Use a list validators from which we will query for /units-for-slot
  • Add a warning that this list has priority, first listed has priority over other validators
  • Include the URLs and maybe even the address of the validator?!
• If a campaign exist in a previous validator, skip any other occurrences of this Campaign
  This has the consequence that the first time a campaign is returned by a validator, it's price (UnitsWithPrice) will be taken into account and all other results from subsequent calls to different validators will be ignored.
• Take the first validator's /units-for-slot result (fallback ad unit, targeting_input_base, accepted_referrers) and use it in the manager at get_next_ad_unit