RFC: Running clang-format across all Plasma (and more?) repos

[David Edmundson]

One topic discussed at the recent Plasma sprint was that we should run
a code formatting tool (clang-format) over all our repos to ease all
future review comments about whitespace.

All new contributions simply have to run the same tool and we get
consistent code without having to comment on every minor thing in a
review individually.

I've written up a wall of text outlining steps, challenges etc.
https://phabricator.kde.org/T11214

Does anyone have any thoughts / objections?

David