feat: support tsconfig extensions

[DonIsaac]

Add support for the extends field in tsconfgs.

Extensions should be done using a TsConfigChain struct that looks like this (note: rough draft, just an idea)

struct TsConfigChain {
    inner: TsConfig,
    parent: Option<Arc<TsConfigChain>>
}

We should keep a resolved tsconfig cache at the monorepo resolver level to avoid redundant file loading.

struct TsConfigCache {
  configs: FxHashMap<PathBuf, TsConfigChain>
}