Add BuildArgs to store common build arguments . ### Description

This renames `ReplayArgs` in pywasmcross to `BuildArgs` and uses it in buildall and buildpkg. No functional changes are involved except for some modifications in function parameters and how logs are copied after the build.

This PR makes it easier to call methods in buildall and buildpkg from the new CLI.

### Checklists

- [x] Add / update tests

# _pyodide is imported at the very beginning of the initialization process so it
# cannot import from js, pyodide_js, or _pyodide_core.
#
# register_js_finder is called from pyodide.js after _pyodide_core is completely
# initialized.
#
# All pure Python code that doesn't require imports from js, pyodide_js, or
# _pyodide_core belongs in _pyodide. Code that requires such imports belongs in
# pyodide.
from . import _base, _importhook

__all__ = ["_base", "_importhook"]

# _pyodide is imported at the very beginning of the initialization process so it
# cannot import from js, pyodide_js, or _pyodide_core.
#
# register_js_finder is called from pyodide.js after _pyodide_core is completely
# initialized.
#
# All pure Python code that doesn't require imports from js, pyodide_js, or
# _pyodide_core belongs in _pyodide. Code that requires such imports belongs in
# pyodide.
from . import _base, _importhook

__all__ = ["_base", "_importhook"]
