Allow changing the label and badge summary

[pawamoy]

I'll bother you once more and after that I think I'll have shared everything with you and you'll have solved all my issues 😅

I'm using the Issue Funding feature as a way for users to boost the priority of issues in my backlog. I don't believe the feature was designed for this use-case, at least not exclusively (since the badge by default says "Upvote and fund"), so I understand if my request is not accepted, or put on a low priority. Here's the request.

My issues don't need funding per-se. I'll get to them eventually. Making pledges merely boosts their priority. I tried making that clear to readers through the description above the badge, but there are still 2 occurrences of the word "fund" that I cannot change/customize:

• the fund label
• and the badge itself saying "Fund this issue"

This can be misleading to readers, as they could think that without funding the issue won't get resolved. But it's not the case.

I would therefore like to be able to change these 2 occurrences to something else, for example a boost label and "Boost issue priority".

Related: #1728 (change fund label), https://github.com/orgs/polarsource/discussions/2621 (customization too).