generate VTY reference manuals from 'make' directly
I just realize that after #3385 (move manuals into project repositories), we can actually generate the VTY reference files on-the-fly when building the manuals and don't need to commit the vty reference XML (and don't need to manually keep that updated, which we hardly ever did).
A prerequisite would be to have osmo-python-tests installed, so the makefile can invoke osmo_interact_vty.py -X.
An alternative which I think is much nicer anyway would be a new cmdline option in each binary that generates this VTY reference to stdout directly, so that we don't need to invoke a telnet nor provide a config file. Like how --version works.
We can then deprecate generating the reference from the vty and also remove the osmo_interact_vty.py -X option.
We have a Jenkins job, that builds each project whenever commits land in master (master-builds.yml, see also). Some of these are built for multiple axes, which means multiple versions will be built with different configure flags enabled. Right now, we have configured the scripts to build the manuals with the fastest job (where the additional features are turned off), so it goes through the fastest way. See the discussion here:
However, neels noted that when we will implement automatic VTY reference manual generation, we would want to do this with a complete build, so we get a full VTY reference manual for all commands. So this would need to be changed as part of this issue.