move various print() to a proper logging mechanism

[mitshell]

Create a proper logging based log() function in each file where it is required, instead of relying on the library-wide log() function from pycrate_core.utils. Move remaining print() calls to those new proper log() functions.

[wgreenberg]

hi! is there any movement on this issue? it'd be great to have for our use of pycrate. otherwise, i could possibly work on it.

[mitshell]

No move yet. Any PR on this will be much appreciated.