Need more number of recent changes displayed

[suhasm]

A large amount of proofreading now happens daily. The recent changes page (https://ambuda.org/proofing/recent-changes) does not show all the changes. It truncates them at some point. I need to see more recent changes, so I can offer feedback to all the proofreaders.

[kvchitrapu]

We should add pagination to the recent-changes page.

Starting point

1. https://github.com/ambuda-org/ambuda/blob/main/ambuda/templates/proofing/recent-changes.html#L17
2. https://github.com/ambuda-org/ambuda/blob/main/ambuda/templates/macros/proofing.html#L174
3. Backend: https://github.com/ambuda-org/ambuda/blob/main/ambuda/views/proofing/project.py#L145

[akprasad]

I'll work on this now.

[akprasad]

Out for review at #485.