rpms: make postgres buffer sizes configurable
mcfg: bug fix, don't fail if target, which is edited only in later increment does not yet exist when earlier increment is executed

affected only target with backup
also more logging added
mcfg: new feature: switchuser

added because postgres configuration is owned by user postgres
of course we could have hacked around as root, but actually this was easy to code
so hopefully it causes less nasty surprises than ugly chmod/chown hacking
dev.rpm: bug fixes to make postgres configuration using mcfg work

- use mcfg switchuser
- fix order of setup scripts (mcfg increments have the same numbers as in the script names, if they
are run otu of order mcfg fails, because file to edited has not yet been patched)
mcfg: obfuscated statement refactored
mcfg: choose realistic Java heap size for servers
Merge remote-tracking branch 'github/master' into uwe-wip5
prod.rpm: bug fix, 2 forgotten symbolic links created
rpms: restore original postgresql.conf file protections
Merge branch 'master' into uwe-wip5
rpms: previous changes built in autobuild on logs updated