feat(init): move templates from core deps to create-electron-app deps

[vhashimotoo]

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

Summarize your changes:

This moves an array of template dependencies from the core package to create-electron-app package and adds a tool that syncs templates with the array.

This is maybe a breaking change for folks that use the electron-forge init command. So 😓. I think it's better to move the command onto create-electron-app usage since this is already proposed by docs and makes more sense.

[malept]

This is 100% a breaking change. Any use of electron-forge init will not work - even the default template (i.e., without the --template flag) will not create anything and error out.

It's also unclear when the new tool in this PR needs to be used. It needs to be documented somewhere that's not in a PR summary / comment.

[vhashimotoo]

This is 100% a breaking change. Any use of electron-forge init will not work - even the default template (i.e., without the --template flag) will not create anything and error out.

What about is to leave this as a breaking change, and hiding init command from cli? Docs already recommend using npx create-electron-app, and I don't think/see many users using electron-forge init approach.

It's also unclear when the new tool in this PR needs to be used. It needs to be documented somewhere that's not in a PR summary / comment.

Are the docs in template/readme or tools/readme appropriate?