twoliter: refactor repetitive setup code

We are doing this too many times:

```rust
let project = project::load_or_find_project(self.project_path.clone()).await?;
let toolsdir = project.project_dir().join("build/tools");
install_tools(&toolsdir).await?;
```

@webern can you suggest a way to factor out the `load_or_find_project` and `install_tools` logic so we don't need to repeat for every command?

_Originally posted by @bcressey in https://github.com/bottlerocket-os/twoliter/pull/230#discussion_r1610786772_

Start by locating the commands that repeat load_or_find_project and install_tools, then read those functions and the surrounding command setup. Determine a shared factoring approach that preserves project loading and build/tools installation across commands. Done means the repeated setup is centralized and all affected commands retain their existing behavior.

Written by the indexing model from the issue text.