Simplify tool_categories in PEGR

[AliNemat]

Currently each Galaxy API tools needs to provide a toolCategory in its payload. All values for toolCategory values are written one by one in galaxy-pegr communication config file. This config needs to be updated if the galaxy tool is updated.
1-The toolCategory values readable and used by PEGR needs to be documented.
2-The number of required toolCategories should be minimum and include only those that are neccessary.
3-preferabbly come up with better strategy which does not require all info manually included in the config file