Move surface to its own directory

[MightyJosip]

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More discussion in #3421, this PR moves all surface stuff into its own directory. Commit also contain some other changes important for moving modules into their own directories, like the changes to make_docs. Decided to go with surface at first, because it is arguably the most important module, so it deserves its special place. This commit compared to the 3421 doesn't move tests, decided it would be the best if it is done separately.