Separate margin auto classes from spacing classes

[janwidmer]

With PR #26957, the file _spacing.scss was included into the file bootstrap-grid.scss. I do understand the request behind it (Ticket #26371),
but for Projects, where one really only need the bootstrap grid classes, one now gets all the padding and margin spacing classes (ca. 1500 lines of css equals about 33kb more in the minified css).

The current workaround is to copy the content of the file bootstrap-grid.scss into the project to be able to remove the import of the file _spacing.scss.

It would be nice if the include of this file could be optional. As atm conditional imports are not possible in scss, the solution might be to move the margin auto classes (the smaller amount of those spacing classes) in a separated file and import it into bootstrap-grid.scss. Like this, the request of Ticket #26371 is still fullfilled as far as I understand.

[mdo]

No plans to do this, thanks for the feedback though!

[janwidmer]

ok thanks for the feedback. would you accept an PR or do you intentionally want to keep it like this? :-)