Import fix for buildenv 2

In legacy backend, use buildenv pip args only for install

Implement installed_packages for legacy env backend

Minor fix for legacy backend implementation

API update for buildenv 2

Fix logging shutdown for Windows unit tests

Fix type hinting for python 3.10

Support int and bool config override from command line -- resolves #255

Handle delayed log file init + changed default log file -- resolves dynod/nmk#269

Fix log exception when using standard loggers in contributed python code -- Resolves dynod/nmk#267

Add --log-prefix option

Fix duplicated refs resolution for dict/list items

Fix referencing config item type -- resolves #252

Handle config item refs escaping -- resolves #242

New PACKAGESREFS build-in item -- part of #256