expand on alternatives that were considered and rejected for sidecars

[Joseph-Irving]

Here's my first pass at expanding this section, let me know what you think

[rata]

@Joseph-Irving Thanks a lot, this is really useful! Do you think you can find a link to where the decision was taken (like comments on github, etc.) for each of the alternatives?

Added a few suggestions to make alternatives titles more descriptive, let me know what you think

[Joseph-Irving]

I can find some of the comments on github discussing some of these things, however, if you want some kind of record of a definitive decision being made on each of these alternatives that probably doesn't exist. The decision was made when the KEP approvers from Sig-apps and Sig-node approved the KEP and allowed it to be merged, so there's no record of them rejecting the alternatives only of them accepting the current proposal. Also just because something did get rejected earlier doesn't mean it never gets discussed again. I've had the same conversation with many people about the same things often reaching the same conclusion. Perhaps if we started something like this from the beginning that would've at least helped to reduce endless debates on the same topic.

[rata]

@Joseph-Irving I think those links might help, and maybe we can add what you say here too: We added some links to where part of the discussion happened and mention that there are no records of some alternatives and the discussions were repeated arriving to the same conclusions, and we hope that adding this section would at least give some context to the reader and save time if we will arrive to the same conclusion.

What do you think?

[Joseph-Irving]

I added all the links I could find, I may have missed something, there's a lot of discussion spread over many PRs.

[rata]

LGTM, thanks a lot @Joseph-Irving ! :)