## Description

Some folks were seeing docs file changes when building `sui-framework`
because of residual `build` directories in their repo. The output
produced in CI was *also* broken, but for a different reason -- it
couldn't find the location of docs for dependencies.

This change fixes both of those issues by building all system packages
in the same "install_dir" (the root of the `sui-framework` crate), and
building `sui-framework` before `sui-system`.

## Test Plan

Remove all `build` directories in `sui-frameworks`, run:

```
crates/sui-framework$ touch build.rs && cargo build
```

Then make sure docs don't change.