Modified getalldelchals of API for delivery notes

Modified getalldelchals of API for delivery notes so that godown in charge is only able to view list of delivery notes that involve their assigned godowns.
Also removed print statement and comment of try/except in GET for single delivery note.  
Closes #351 

See merge request !13

Modified getalldelchals of API for delivery notes so that godown in charge is only able to view list of delivery notes that involve their assigned gidoowns.
Also removed print statement and comment of try/except in GET for single delivery note.

GSTIN is sent in invoice get

GSTIN is added to the dictionary inv.

See merge request !12

Prevented redundancy in product get for godownkeeper

When a list of product codes is created in api_product.py for godown keeper a productcode was being added in every pass of loop.  
Now a condition checks if the productcode is already available and appends it to list only if it is not.

See merge request !10

Organisation GSTIN

Organisation's GSTIN getting in proper way.

See merge request !11

Function thats retuns Userrole

A new function in api_user.py that returns userrole  
It receives userid from gktoken and calls getuserole to fetch userrole  
closes #358 

See merge request !9

Transfernote

Godown keepers gets to see only transfernotes sent to them  
closes #356

See merge request !7

Cess taxrate columns added in registers.

All conditions are considered:  
* When cess field is empty.    
* when cess field has value.    
* when cess field has empty dict (in VAT case).

See merge request !8

subtract frpm qty

Changes in Invoice and Product GET

Edited Invoice GET so that Sales and Purchase Invoices separated in View Invoice   
Number of godowns in Product GET called by godown keeper considers only the godowns assigned.  
Considered godown keeper's godowns in getProductByGodown

See merge request !6

In case of godown keeper number of godowns in Product GET considers only the godowns assigned to godown keeper

added missing gsflag field in query in API_PRODUCT get all products

See merge request !5