Builders and package classes refer to packages from the builtin package
repo and are often modified together with packages. That means that
these classes should move into `spack_repo.builtin`.
* move `spack.build_systems` -> `spack_repo.builtin.build_systems`
* Remove the following re-exports from the `spack.package` module:
- `AspellDictPackage` - `LuaPackage`
- `AutotoolsPackage` - `MakefilePackage`
- `BundlePackage` - `MavenPackage`
- `CachedCMakePackage` - `MesonPackage`
- `cmake_cache_filepath` - `MSBuildPackage`
- `cmake_cache_option` - `NMakePackage`
- `cmake_cache_path` - `OctavePackage`
- `cmake_cache_string` - `PerlPackage`
- `CargoPackage` - `PythonExtension`
- `CMakePackage` - `PythonPackage`
- `generator` - `QMakePackage`
- `CompilerPackage` - `RacketPackage`
- `CudaPackage` - `RPackage`
- `Package` - `ROCmPackage`
- `GNUMirrorPackage` - `RubyPackage`
- `GoPackage` - `SConsPackage`
- `IntelPackage` - `SIPPackage`
- `IntelOneApiLibraryPackageWithSdk` - `SourceforgePackage`
- `IntelOneApiLibraryPackage` - `SourcewarePackage`
- `IntelOneApiStaticLibraryList` - `WafPackage`
- `IntelOneApiPackage` - `XorgPackage`
- `INTEL_MATH_LIBRARIES`
* update mock packages to repo v2.0 and add copies of packages/build
systems they use from builtin
* add missing imports to build systems in `package.py` from builtin
and test repos
* update various tests
This PR is breaking because of removal of various names from
`spack.package`, but breakage should be minimal thanks to #50496, which
ensures the above names are always imported in repo v1 packages.
Specifically this PR breaks imports like the following in `package.py` files:
```python
from spack.package import Package
```
but if your repo is v1.0 (see `spack repo list`) and has the following
much more common pattern:
```python
from spack.package import *
```
nothing should break.