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

Beta Give feedback

1. Fix & Deploy referenda
2. Reapply https://kusama.polkassembly.io/referenda/205 -> paritytech/substrate#13993,
3. Reapply https://kusama.polkassembly.io/referenda/206 -> paritytech/substrate#13027,
4. Reapply https://kusama.polkassembly.io/referenda/207 -> paritytech/cumulus#2294
5. 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