refactor(esbuild): wrap all the logic inside a plugin

[oscard0m]

Description

Wrap all the logic of scripts/build.mjs in an in-house ESBuild plugin.

The idea would be to publish our ESBuild Octokit plugin and centralize the changes we want to do in the future.

We would need a /scripts/build.mjs which calls ESBuild with this plugin but that should remain static (and still would have the door open to passing options to our plugin in case we have a repo with special requirements).

@wolfy1339 What do you think about this?

[wolfy1339]

This looks good and I like the idea.

We'd most likely have to get another repo and npm package set up for this

[oscard0m]

This looks good and I like the idea.

We'd most likely have to get another repo and npm package set up for this

I propose doing this:

1. Let's land build: replace pika with esbuild and tsc #819 and we can see if this causes friction to users or not and land the appropriate fixes if necessary. Let's wait before scaffolding this to the rest of the repositories.
2. I'll update this PR to make it a refactor of what you land in step 1 and I will tag the core team to see if they like the idea and ask for that repo and npm package.
3. Depending if they take time to answer or not we can publish it in our personal GitHub until we get an answer but I hope to get an answer soon (and I hope they like the idea).

Sounds good to you? @wolfy1339

[wolfy1339]

Absolutely sounds good 👍