Excessive memory usage in monorepos with dozens/hundreds of cabal packages or modules

* There are several issues about memory consumption but it seems it is exacerbated in those contexts
* The large public codebase where hls works reliably is ghc but it has few packages
* Test performance of large monorepos is hard:
* They usually are private
* Setup a benchmark here would be pretty difficult
* So we need the feedback of users to improve perfomance in those scenarios
* Pinging the experts om the subject: @wz1000, @mpickering, @pepeiborra, @fendor
* I think @parsonsmatt has experienced this issue
* As a first step we should analyze where is the culprit, starting from hie-bios