algo: Move histogram sending into own class and add flag for server address.

@p.-a.loizeau, some more integration of the histogram sender into the online binary.

docs/histservs/HowTo.md

@@ -139,11 +139,8 @@ For an example of this, please have a look at `algo/qa/DigiEventQa` and `algo/ev
 
 ### Usage with the `cbmreco` binary
 
-1. Controlling the histogram emission behavior in `cbmreco` binary \
-   Comment/Uncomment one of the two lines defining `fHistComChan` in `algo/evbuild/EventbuildChain.h` then recompile.\
-   => An empty string disables the histogram emission
-2. Start the server exactly as in the tested app example
-3. Start `cbmreco` as usual (no CLI option/parameter for this feature for now)
+1. Start the server exactly as in the tested app example
+2. Start `cbmreco` as with `--histogram <address>`
    ```
-   ./cbmreco -p <path to algo params> -i <file://path-to-tsa-file or tcp://url-of-ts-server> --steps Unpack DigiTrigger Localreco
+   ./cbmreco -p <path to algo params> -i <file://path-to-tsa-file or tcp://url-of-ts-server> --steps Unpack DigiTrigger Localreco --histogram <address>
    ```