When CONFIG_FILES setting is not used, the caikit-nlp config values
are not read from environment variables unless caikit has already
imported caikit-nlp.  The code was loading the embedding config too
soon in this case so the env vars were ignored.

This commit reads the config during bootstrap and load for settings that are needed
at bootstrap/load time and also reads config during module init for runtime settings.

In addition:

* bootstrap() kwargs can be used (e.g. for trust_remote_code param)
* load() was made to work with model_path as ModuleConfig (because str is deprecated and spammy)
* utils/env_val_to_int was removed because the caikit config handles this well
* utils/env_val_to_bool was NOT YET removed because the caikit config does not handle this quite as well

Signed-off-by: Mark Sturdevant <[email protected]>

ModuleConfig should always have a model_path, but this check will
make the error better if this gets called with an empty ModuleConfig.

Signed-off-by: Mark Sturdevant <[email protected]>

Signed-off-by: Mark Sturdevant <[email protected]>