Import kube-rt

[clux]

A WIP import that aims to get to point 1 of #148 (comment)

Marking down some key points:

• imported kube-rt codebase (impersonated Theo for initial dump, since he wrote all of it)
• made it work as part of workspace with joint examples dir
• consolidate dev-deps
• migrate from kube-runtime to kube/src/runtime or kube/src/runtime2

The latter migration requires consolidating the normal dependencies and dealing with some unpublishable things:

• deal with pin-cell git dependency - cannot just use 0.1.1 due to:

error[E0554]: `#![feature]` may not be used on the stable release channel
 --> /home/clux/.cargo/registry/src/github.aaakk.us.kg-1ecc6299db9ec823/pin-cell-0.1.1/src/lib.rs:3:1
  |
3 | #![feature(pin, arbitrary_self_types)]
  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

• deal with #[project] deprecated attr warning

warning: use of deprecated item 'project': consider naming projected type by passing `project` argument to #[pin_project] attribute instead, see release note <https://github.com/taiki-e/pin-project/releases/tag/v0.4.21> for details
  --> kube-runtime/src/scheduler.rs:59:3
   |
59 | #[project]
   |   ^^^^^^^

• unify error handling (move to snafu + inside kube + color_eyre inside examples)
• migrate examples from old runtime to new runtime
  Maybe try to also get examples as a top level directory. Tried that before, but it was slightly annoying with workspaces

[clux]

Replaced by #258