As explained on the issue #124
This commit adds the projects dependencies list on the plugin context

Before:
```typescript
import { hasRubyDependency } from "./dependencies.ts";

const isDependency = await hasRubyDependency(context, "rubocop");
```
At every import and function call the application would go on the
dependencies files(package.json, Pipfile, etc ...) and search for
the requested dependencies. This made the application very slow
in addition to harming the organization of the code with many unnecessary imports.

After:
```typescript
const isDependency = await context.dependencies.includes("rubocop");
```
Now the dependency list is loaded before the introspection and
only need to read the necessary dependencies files once.

Resolves: #124