[build] Move to python build scripts per module

This change moves Bonnibel from a separate project into the jsix tree,
and alters the project configuration to be jsix-specific. (I stopped
using bonnibel for any other projects, so it's far easier to make it a
custom generator for jsix.) The build system now also uses actual python
code in `*.module` files to configure modules instead of TOML files.
Target configs (boot, kernel-mode, user-mode) now moved to separate TOML
files under `configs/` and can inherit from one another.

scripts/bonnibel/source.py

@@ -0,0 +1,78 @@
+class Action:
+    name = property(lambda self: self.__name)
+    implicit = property(lambda self: False)
+    rule = property(lambda self: None)
+
+    def __init__(self, name):
+        self.__name = name
+
+    def output_of(self, path):
+        return None
+
+
+class Compile(Action):
+    rule = property(lambda self: f'compile_{self.name}')
+
+    def __init__(self, name, suffix = ".o"):
+        super().__init__(name)
+        self.__suffix = suffix
+
+    def output_of(self, path):
+        return str(path) + self.__suffix
+
+
+class Parse(Action):
+    rule = property(lambda self: f'parse_{self.name}')
+
+    def output_of(self, path):
+        suffix = "." + self.name
+        if path.suffix == suffix:
+            return path.with_suffix('')
+        return path
+
+
+class Link(Action): pass
+
+
+class Header(Action):
+    implicit = property(lambda self: True)
+
+
+class Source:
+    Actions = {
+        '.c': Compile('c'),
+        '.cpp': Compile('cxx'),
+        '.s': Compile('asm'),
+        '.cog': Parse('cog'),
+        '.o': Link('o'),
+        '.h': Header('h'),
+    }
+
+    def __init__(self, root, path, output=None, deps=tuple()):
+        from pathlib import Path
+        self.__root = Path(root)
+        self.__path = Path(path)
+        self.__output = output
+        self.__deps = deps
+
+    def __str__(self):
+        return "{} {}:{}:{}".format(self.action, self.output, self.name, self.input)
+
+    @property
+    def action(self):
+        suffix = self.__path.suffix
+        return self.Actions.get(suffix)
+
+    def get_output(self, output_root):
+        if not self.action:
+            return None
+
+        path = self.__output
+        if path is None:
+            path = self.action.output_of(self.__path)
+
+        return path and Source(output_root, path)
+
+    deps = property(lambda self: self.__deps)
+    name = property(lambda self: str(self.__path))
+    input = property(lambda self: str(self.__root / self.__path))