WIP: (for discussion) add topics to accept

[vrolland]

Description of the changes

Give the opportunity to add topics when accepting a request.

⚠️ This is only for discussion purpose. ⚠️

[MantisClone]

Some questions:

• What use case does this feature serve?
  • This idea was motivated by a hacker at ETHRome who wanted to retrieve and filter requests by an arbitrary identifier. They gave the example of wanting to see all requests that are television purchases.
  • They wanted to apply these arbitrary identifiers to existing requests.
• Should all actions allow adding topics?
  • I don't see a problem with this.
• Should there be an addTopic() action in case someone only wants to add a topic without performing some other action?
  • If we implemented this feature, I think addTopic() would be a necessary part of it.
• Does there need to be some sort of consensus between payer and payee to add a topic?
  • Honest question. I'm leaning towards no, but I'm not sure of the implications.
• Can any stakeholder add a topic?
  • Honest question. I'm leaning towards yes, but I'm not sure of the implications.

[MantisClone]

@vrolland Sorry this fell through the cracks. I just added it to the Request Network Tech Backlog and we'll be able to assign priority to this task at our next backlog refinement.