Enhance Proposal Sorting Options

[ori-near]

Problem

Users need more ways to sort proposals to find what they're looking for quickly. We've received a few tickets around this topic (#721, #903), and this issue attempts to consolidate the feedback into one ticket.

User Story

As a user browsing proposals (on any instance), I want to sort them in the way that fits my particular workflows.

Acceptance Criteria

• User can sort by date created (oldest to newest, and vice versa)
• User can sort by last updated (oldest to newest, and vice versa)
• User can sort by number of comments