Allow skipping directories during type generation

[OliverGilan]

Add an app-level typeIgnore config and thread it into SST's project discovery so JavaScript and Python projects can opt out of generated type files.

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Problem

In a monorepo with many packages, a lot of them have nothing to do with SST yet SST insists on generating its types file in every directory where it finds a package.json or pyproject file.

Solution

This PR adds a simple config to ignore certain directories for type generation files

[vimtor]

thanks for your contribution @OliverGilan

could you take a look at #6675? maybe we could reuse its existing watcher.ignore (although watcher makes less sense in this context)

[OliverGilan]

@vimtor I thought about doing that, it would definitely be cleaner than introducing a whole new config setting but I believe what I ran into is that the watcher doesn't run in all contexts where typegen happens. For example sst deploy will generate types but I don't believe there's any watcher in that context.

I think for our purposes that's not a huge deal because we only deploy in CI so we could go that route if you prefer