ICS ?: IBC threat model & security assumptions

[cwgoes]

Primarily a port of the original IBC spec.

Will cover:

• Security assumptions of the underlying consensus
• Required slashing conditions / evidence handling
• Exceptional cases and possible recovery methods

[cwgoes]

Could possibly be merged into #25, not sure if these are sufficiently distinct to warrant separate specs.

[mossid]

I think Security assumption can be merged into #25, Exceptional cases and recovery methods can be merged into #6, and slashing conditions / evidence handling can be merged into #10 and separated into a new issue, perhaps validator remote slashing on Application layer section.

[cwgoes]

I think Security assumption can be merged into #25, Exceptional cases and recovery methods can be merged into #6, and slashing conditions / evidence handling can be merged into #10 and separated into a new issue, perhaps validator remote slashing on Application layer section.

Perfect, done.