feat: follow a space

[bonustrack]

For Snapshot spaces only, we should replace favorite icon on space overview with a button "Follow" like this:

When followed, the label should be "Following" like this:

On mouse over if already followed, it should show "Unfollow" in red like this:

Instead of adding the space in the localStorage like favorite, it should send an action to Snapshot sequencer to do a follow. This require session key, or "alias". This is something we do on Snapshot, when someone try to follow a space for the first time, we generate an Ethereum private key and store it in local storage with a corresponding logged user address, then we sign a message from the logged wallet to give authority to the session key to be used to do action like follow. Then we can do a follow action with the session key (signing in the browser without going through the wallet). The session key should only be created when needed (on first follow), we don't want to have signing wall on user arrival.

We should also display the followed spaces on the very left sidebar, (along with favorites)

This can be done in a separated PR.

Tasks

Beta Give feedback

1. Load an account's follows list from the hub (done via feat: add timeline #217)
2. Show followed spaces in the sidebar feat: replace favorites by follows (read-only) #288
3. Replace "favorite" by "follows/unfollows" in v1 space feat: replace favorites by follows (read-only) #288
4. Send follow/unfollow actions to the sequencer feat: support spaces follow and unfollow #293
5. Implement alias system for voting without signature feat: add session keys (alias) for offchain spaces #294

[wa0x6e]

Should we extract the session key in another PR, or keep in this one ?

And do starknet address can also follow snapshot space, or do we restrict it to only EVM address ?

[bonustrack]

The more we separate the better is it IMO. And we should not support SX spaces or Starknet wallet.

[wa0x6e]

So we should disable following for users logged in with starknet wallet ? Just disable or fallback to favorite like now ?

[bonustrack]

We can remove the button for Starknet user on Snapshot space

[wa0x6e]

Do we also add followed spaces in the sidebar ?

[bonustrack]

Yes