scss variables: use either $spacer, $r-spacer, or $padding

[fuzzylogic2000]

URL: user: expected behaviour: behaviour: important screensize: device & browser: Comment/Question: We use all three, and they are all 1rem, so I think, we should decide on one and use it everywhere. Or do we need one or all of these for the bootstrap classes as well? https://github.com/liqd/adhocracy-plus/blob/809d90c1af6984a20f2c588463ecdf55050fb8d7/adhocracy-plus/assets/scss/_variables.scss#L83

Screenshot?

[fuzzylogic2000]

Or we can also use the same everywhere like $padding for padding and $spacer for everything else. Just having it the same everywhere would be nice!