Document separate "build" from "minify/uglify" tasks in grunt

[jywarren]

@publiclab/is-reviewers this was suggested already but we didn't follow-up, so I'm opening a new issue for it. It seems this exists now, but it's not well documented.

Copying in the last note from that issue via @harshkhandeparkar on this distinct issue:

Yes. Definitely. I think the gruntfile should be revised. Its very messy as of now. The ui dist files are not built in the build task. All the targets of a task are mentioned whereas the whole taskname can be used. Like instead of adding browserify:dist browserify:js uglify:dist uglify:js to the build task, browserify ulgify is enough. Etc. Can somebody open a new issue for that or do taht directly?

So, I think we currently have:

1. grunt build - just do everything below
2. grunt browserify - just generate dist/image-sequencer.js
3. grunt uglify - minify dist/image-sequencer.jstodist/image-sequencer.min.js`

Is this correct? I believe we could also better show building UI files, so instead of current grunt browserify:js it should be grunt browserify:ui?

https://github.com/publiclab/image-sequencer/blob/main/Gruntfile.js#L56

Let's especially make it clear to people that:

1. you don't need to submit /dist/ files (as per Managing dist files #601) in PRs
2. while developing you don't need to run full grunt build but only grunt browserify?

Is this correct?

[jywarren]

Reopening just so we can add better documentation to newcomers using this! (and oldcomers since it changed 😄 )

[harshkhandeparkar]

Fixed in #897