WIP: readonly hosts
add missing integration test
implementing fetching of readonly status of missing services
set one IT to fetch RO-service from remote host

also improved verification of status calls with RO-hosts as the RO
fetches are sequential
initialize appropriate defaults in settings.py
simplify tests using the SSH setting
Added tests for component ReadOnlyService
first step to render read only hosts/services
Merge branch 'feature/readonly_status_OSLT' of github.com:yadt/yadtshell into feature/readonly_status_OSLT
store components locally _after_ any additional modifications (like querying readonly services)
remember needed_by relations when handling readonly service
improve rendering of problematic components
render readonly services below service matrix, just as text (for a start)
ignore some layout-centric tests while developing the info rendering of readonly services
make flake8 happy
add missing assertion
set default setting value for services
add test for filtering missing services
added status tests for readonly states
implement readonly service pseudo-mutation