ICS28: Remove CCV channel state (#678)

* Create README.md

* Add files with CCV spec

* fix links to ICS 4

* fix links to ICS 7

* add ICS 28 to main README.md

* adding tech spec for unbonding delegations

* add context on unbonding operations

* add unbonding operation diagram

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Sergio Mena <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Sergio Mena <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/system_model_and_properties.md

Co-authored-by: Sergio Mena <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/technical_specification.md

Co-authored-by: Sergio Mena <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/README.md

Co-authored-by: Sergio Mena <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/README.md

Co-authored-by: Sergio Mena <[email protected]>

* minor, remove confusing phrasing

* child -> consumer; parent -> provider

* clarify which staking module

* extend staking assumptions, remove redundant inv, prove staking props and sys inv

* modify staking hooks spec to cover other unbonding ops

* provider Staking module

* break long lines

* break long lines

* remove dependecies to Cosmos SDK

* changes in the security model

* specify multiple consumer chains

* channel init overview

* address issues #27 and #33 from cosmos/interchain-security repo

* extend consumer InitGenesis

* describe mechanism to disseminate genesis state

* describe mapping heights provider <> consumer

* remove ExportGenesis and restarted chains

* add overview of consumer initiated slashing

* add slashing invariant

* add assumptions needed by evidence

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Josef Widder <[email protected]>

* draft CCV props for slashing

* replace time w/ height; add HtoVSC and VSCtoH

* replace time with height in invariants and properties

* validate channel IDs on provider genesis

* prove Slashing Invariant

* enable mapping from consumer to provider heights

* technical spec for slashing

* minor changes

* fix links to tendermint spec

* clarify Staking vs Slashing modules

* replace VSC acks w/ VSCMaturedPackets

* fix some TODOs

* fix properties

* HtoVSC and VSCtoH from () to []

* fix infraction height and add intuition diagram

* keep ValidatorSet in consumer CCV module state

* remove CCV channel status

* add outstanding downtime flag and decouple from validatorSet

* adressing Josef's comment

* fix issues pointed by Simon

* dealing with downtime slashing atomicity

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Aditya <[email protected]>

* addressing Aditya's comments

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Josef Widder <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Josef Widder <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/overview_and_basic_concepts.md

Co-authored-by: Josef Widder <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/technical_specification.md

Co-authored-by: Josef Widder <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/technical_specification.md

Co-authored-by: Josef Widder <[email protected]>

* addressing Josef's comments

* link TODOs with issues

* Update spec/app/ics-028-cross-chain-validation/system_model_and_properties.md

Co-authored-by: Aditya <[email protected]>

* Update spec/app/ics-028-cross-chain-validation/system_model_and_properties.md

Co-authored-by: Aditya <[email protected]>

* apply suggestions from code review

* cleanup outdated note on restarted consumer chains

Co-authored-by: Sergio Mena <[email protected]>
Co-authored-by: Josef Widder <[email protected]>
Co-authored-by: Aditya <[email protected]>