imjournal: add availability and dependency info
Merge pull request #96 from rsyslog/v7-stable-th-imjournal-info

imjournal: add availability and dependency info
Merge branch 'v7-stable' of https://github.com/rsyslog/rsyslog-doc into v7-stable
fix typo in code sample

thanks to Volker Fröhlich for pointing this out
Merge branch 'v7-stable' into v8-stable