Fix style-spec scripts to work in esm package/fix help

[acalcutt]

Attempt to fix #1963

This PR updates the syntax of the style-spec bin scripts to be ESM syntax and adds a file extension to fix the following error
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension "" for /root/.nvm/versions/node/v16.15.0/lib/node_modules/@maplibre/maplibre-gl-style-spec/bin/gl-style-migrate. Loading extensionless files is not supported inside of "type":"module" package.json contexts. The package.json file /root/.nvm/versions/node/v16.15.0/lib/node_modules/@maplibre/maplibre-gl-style-spec/package.json caused this "type":"module" context. Try changing /root/.nvm/versions/node/v16.15.0/lib/node_modules/@maplibre/maplibre-gl-style-spec/bin/gl-style-migrate to have a file extension. Note the "bin" field of package.json can point to a file with an extension, for example {"type":"module","bin":{"gl-style-migrate":"./bin/gl-style-migrate.js"}}

it also adds missing help information for 'gl-style-migrate' which did not exist before.

It also removes 'gl-style-composite' for #1981

• Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
• Briefly describe the changes in this PR.
• Link to related issues.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality.
• Document any changes to public APIs.
• Post benchmark scores.
• Add an entry to CHANGELOG.md under the ## main section.

[github-actions]

Bundle size report:

Size Change: 0 B
Total Size Before: 207 kB
Total Size After: 207 kB

Output file	Before	After	Change
maplibre-gl.js	197 kB	197 kB	0 B
maplibre-gl.css	9.1 kB	9.1 kB	0 B

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No major changes

[HarelM]

The type in the package.json file of the style-spec is defined as module which assumes js files are esm now and not cjs.
I would recommend changing the scripts to use import instead of require and not keep them in common js format.
If this avoids the need to rename them, I think it's a better option...

[acalcutt]

I mentioned changing these extensions to cjs is probably the wrong approach in the issue thread, which is why this is still a draft. This works but those scripts should be easy to convert since they are small

I was planning to attempt to change it to ESM syntax next, I just wanted to submit what I got working last night before I went to bed.

[HarelM]

Sorry, didn't mean to jump too soon. Thanks for looking into this!

[acalcutt]

I've tested this with
npm i -g @acalcutt/maplibre-gl-style-spec@17.0.7

and basic-v7.json as a test file

[zstadler]

I've tested all scripts with a few of styles here. They all work flawlessly.

[HarelM]

Thanks!
Can you please add a changelog item in both style-spec and the main one and bump the version of style-spec so that we can release a new version of it?

[acalcutt]

I added the changelogs and updated the version