* Add alex to build-tool-depends and remove separate code gen

- Pass latin-1 encoding is passed as input pragma
- Cabal hard-codes -g for alex so we don't need to worry about --ghc
- Rework bootstrap, adding per-component building
- Update bootstrap plans

* [bootstrap] warn the user if cabal config is not found

* [bootstrap] regenerate bootstrap plans once more

* [bootstrap] regenerate bootstrap files after #9139