Makes SPs first class citizens along with the relay chains in the
context of our CI runtime upgrade checks.

## Code changes

- Sets missing current storage version in `uniques` pallet
- Adds multisig V1 migration to run where it was missing
- Removes executed migration whos pre/post hooks were failing from
collectives runtime
- Initializes storage versions for SP pallets added after genesis
- Originally I was going to wait for
https://github.com/paritytech/polkadot-sdk/pull/1297 to be merged so
this wouldn't need to be done manually, but it doesn't seem like it'll
be merged any time soon so I've decided to set them manually to unblock
this

## CI changes

- Removed dependency of `westend` runtime upgrades being complete prior
to other ones running. I assume it is supposed to cache the
`try-runtime` build for a performance benefit, but it seems it wasn't
working. Maybe someone from the CI team can look into this or explain
why it needs to be there?

- Adds check-runtime-migration jobs for Parity asset-hubs, bridge-hubs
and contract chains

- Updated VARIABLES to accomodate the `kusama-runtime` package being
renamed to `staging-kusama-runtime` in
https://github.com/paritytech/polkadot-sdk/pull/1241

- Added `EXTRA_ARGS` variable to `check-runtime-migration`, and set
`--no-weight-warnings` to the relay chain runtime upgrade checks (relay
chains don't have weight restrictions).