raco pkg create: support "source" and "binary" bundling

Adds `--from-dir' and `--from-install' flags to select the interpretation
of the argument as a directory or as the name of an installed package.
Relevant to PR 13669

Adds `--as-is' (the default), `--source', and `--binary' flags to
select a pruning mode.

The `raco setup' tool recognizes a `rendered-scribblings' specification
in "info.rkt" to trigger moving rendered documentation into place,
registering its tags in the cross-reference database, and fixing up
references to "local-redirect.js"; the presence of a "synced.rktd"
indicates when those fixups have been performed (since, if the package
is installed in a user-specific scope, the documentation doesn't actually
move anywhere). Finally, "out<n>.sxref" needs to report paths relative to
the documentation's directory, and then the relative-directory references
need to be suitably resolved at derserialization; some support for such
relative paths was in place, but it wasn't quite general enough before.

original commit: 198a65a5fc

collects/tests/pkg/test-pkgs/pkg-z/info.rkt

@@ -0,0 +1,2 @@
+#lang setup/infotab
+