Rework loading of config files

[fbartels]

With the effort of making the containers read-only config files were moved to /tmp and startup scripts were adapted and wrapper scripts were introduced to handle calling e.g. kopano-admin with the config from /tmp.

With KOPANO_CONFIG_PATH there does however exist an environment variable that can influence from where all services read their configuration.

Code at https://stash.kopano.io/projects/KC/repos/kopanocore/browse/common/ECConfigImpl.cpp#128-159

The startup script should be reworked again to make use of this variable and remove the wrappers again.

[fbartels]

Found this while researching when it was introduced:

https://fisheye.zarafa.com/changelog/ZarafaSVN?cs=28104 (that system is not publicly reachable)

Create GetDefaultConfigPath function that returns the default full path for a configuration file, where the base path can be controlled using the ZARAFA_CONFIG_PATH environment variable.
Update zarafa-dagent, zarafa-spooler, zarafa-admine and zarafa-archiver to make use of this function.

For #7269

12.07.2011