Allow two Parachains to swap (#4772)

* add support for parachain to parachain swap

* enable swaps on kusama

* sanity test in paras_registrar

* express more errors

* finish up tests

* fmt

* make fields pub

* refactor integration tests to use real accounts

* Update Crowdloan Account to FundIndex (#4824)

* update fund account to use index

* fix integration tests

* Update runtime/common/src/crowdloan.rs

* finish parachain swap test

* format

* fix warning

* fix spacing

* fix formatting

* write migrations

* add migration

* fixes

* more fixes to migration

* Update runtime/common/src/crowdloan/mod.rs

Co-authored-by: Zeke Mostov <z.mostov@gmail.com>

* Update runtime/common/src/paras_registrar.rs

* Update migration.rs

* extract swap function

Co-authored-by: Zeke Mostov <z.mostov@gmail.com>