A lot of server-side changes were just merged as part of the Brandon
project (crypto). Many of those changes were in libspark (a lib on
which both the client and server depend), and upgrades to its external
dependencies. As a result, windows counterparts of several upgraded
external libs needed to be similarly upgraded (or added for the first
time). These libs include: boost, btree, catch, curl, fmt, nlohmann json,
openssl, range, rxcpp, websocketpp
This change also makes protobuf generation compatible with python3, and thus
eliminates the build's dependency on python2
* Automatically create python virtual envs
* Automatically actvate the vs dev prompt
Note: the python39 virtual env will remain active in the calling shell.
This behavior may be changed down the road.