Add a system defination file template generator.

*.prm files in old test sets(ASTEX_rDock_TestSet,DUD_rDock_TestSet,RNA_rDock_TestSet) cannot be parsed in branch 307d7d54.
I wrote a script to generate system defination file templates according to the files in specified directories recursively.
It can generate json files for rxcmd cavity-search -r or rxcmd dock -r in old test sets.
In my computer,several cavity-search,dock,rmsd tests were performed and no obvious wrong happened.
It can also provide some help to users who don't know how to write system defination files manually.
I didn't find which source script do this.
The default key-value pairs are inferred from the source code and test examples,which may not be completely right.
I don't know how to set the default value of segment-name to make rxdock skipping segment-name parsing.0 and false both lead to BAD_RECEPTOR_FILE error with information:File source contains zero atoms! Have you defined RECEPTOR_SEGMENT_NAME correctly?' So in this script I skippedsegment-name`.