document control protocol router status format surprises when using microdescriptors

In Tor 0.3.0 (or earlier?), we made clients use microdescriptors by default. This changes the format of NS_CONTROL_PORT routerstatus lines, which breaks pytorctl, and therefore the bandwidth authorities.

Apparently, this issue can be resolved by setting UseMicrodescriptors 0 or using 0.2.9.

edit: Let's update control-spec.txt to document the current (surprising) behavior and track further behavior improvements in other tickets.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information