bug: Set a more lax (and dynamic) type for election.meta than object

[elboletaire]

Describe the bug

Current type for PublishedElection meta field is set to object, and this complicates things for end developers. Given we use a recursive key value object where values can be either strings or objects of the same type, I suggest setting a recursive type like

type ElectionMeta = {
  [key: string]: ElectionMeta | string
}

Note this should be properly tested since I'm not sure just setting it recursive in this way would work or not...

Current behavior

election.meta is of type object, forcing typescript developers to always use as any to properly access values:

const tokenDecimals = (election.meta as any).token.decimals

Expected behavior

To be able to access any election.meta subfield without requiring to add as any everytime:

const tokenDecimals = election.meta.token.decimals