Index past treasury proposal

[stephanie-olp]

We would like to add the past treasury proposals in the app: the one that passed but also the one that didn't

[stephanie-olp]

Data to be indexed:

• Proposal ID
• Title of the proposal (if there is one)
• Proposal Description (if there is one)
• Proposer
• Beneficiary
• Status
• date of creation
• date it became a council motion (if there is one)
• Reward
• Link to Polkassembly discussion

[stephanie-olp]