Each poll of a host's overview graph held a worker for one second between
two CPU samples. The answer now carries its sample, signed with the time
and the compute; the next poll sends it back and the usage is taken since
then, so a point is the average since the previous one (normally 5 s, at
most 15 s). Without a sample, or with one that is altered, older or from
another host, or when the host restarted, it is measured over one second
as before.
A sample is one reading; the busy share was mixed from separate readings,
counted guest time twice (it is part of user) and added half a percent.
A host that cannot be read leaves a gap in both graphs instead of a zero
CPU point and a broken memory axis.
* Add rest framework for API: First Commit
* modify some shell scripts to make variable references safer; modify some python scripts to reduce the code complexity and cyclomatic complexity of functions.
* Add REST API for some webvirtcloud functions. Instance list/delete/create, compute list/delete/create, storages-network list/retrieve. Add swagger and redoc for API interface
* update requirements
Co-authored-by: herengui <herengui@uniontech.com>
