Store tip metadata through `set_metadata` instead of a remark

[rzadp]

Remark is not possible at the moment and breaks the referenda.
(But might be possible after paritytech/substrate#14260). Still, metadata is preferred.

### Tasks
- [x] Fix & Deploy referenda
- [x] Reapply https://kusama.polkassembly.io/referenda/205 -> https://github.com/paritytech/substrate/pull/13993,
- [x] Reapply https://kusama.polkassembly.io/referenda/206 -> https://github.com/paritytech/substrate/pull/13027,
- [x] Reapply https://kusama.polkassembly.io/referenda/207 -> https://github.com/paritytech/cumulus/pull/2294
- [x] In each new referenda, on polkassembly, leave a comment that it's re-submitting a tip for according PR due to this issue

[rzadp]

New referenda:

• https://kusama.polkassembly.io/referenda/216
• https://kusama.polkassembly.io/referenda/217
• https://kusama.polkassembly.io/referenda/218

cc @mordamax

[rzadp]

Solved by #79