Set DOT supply limit to 1 200 000 DOT

DOT supply cap was reached recently sooner than expected. In order to allow debtors improve their positions by using DOT this proposal increases cap by 50%.
This proposal is whitelisted by TC to remove this bottleneck as soon as possible.

• Supply cap updated 800 000 -> 1 200 000 DOT

This proposal replaces #33 which wasn't executed because of malformed call data.

Proposal decoded

└── whitelist.dispatchWhitelistedCallWithPreimage:
    └── call:
        └── utility.batchAll:
            └── calls:
                [0]
                    └── utility.dispatchAs:
                        ├── as_origin:
                        │   └── system:
                        │       └── Signed: 7MT6raKnJHmp9dVDBt2rZY19WU5wcSukV9aVVDiDHut3Pe3Z
                        └── call:
                            └── evm.call:
                                ├── source: 0xaa7e0000000000000000000000000000000aa7e0
                                ├── target: 0xe64c38e2fa00dfe4f1d0b92f75b8e44ebdf292e4
                                ├── input:
                                │   └── setSupplyCap:
                                │       ├── asset: 0x0000000000000000000000000000000100000005
                                │       └── newSupplyCap: 1200000
                                ├── value: 0
                                ├── gas_limit: 100,000
                                └── max_fee_per_gas: 600,000,000