Rollup merge of #66056 - petrochenkov:metapriv, r=eddyb

rustc_metadata: Some reorganization of the module structure

The new structure of `rustc_metadata` (or rather its parts affected by the refactoring) is
```
├── lib.rs
└── rmeta
    ├── decoder
    │   └── cstore_impl.rs
    ├── decoder.rs
    ├── encoder.rs
    ├── mod.rs
    └── table.rs
```

(`schema` is renamed to `rmeta`.)

The code inside `rmeta` is pretty self-contained, so we can now privatize almost everything in this module instead of using `pub(crate)`  which was necessary when all these modules accessed their neighbors in the old flat structure.

`encoder` and `decoder` work with structures defined by `rmeta`.
`table` is a part of `rmeta`.
`cstore_impl` actively uses decoder methods and exposes their results through very few public methods (`provide` and `_untracked` methods).

r? @eddyb @spastorino

0 files changed, 0 insertions, 0 deletions