Extract constant for page size of load projects calls

[vikasrohit]

Right now its hardcoded anywhere we are passing page size. We need to extract it as constant, it would be easy to manager later when we would make page size dynamic as well.

[sachin-maheshwari]

PR - #1429

[sachin-maheshwari]

not sure if it is known behavior - corresponding back-end API is giving maximum 20 results even limit value is > 20.
https://api.topcoder-dev.com/v4/projects/?limit=50&offset=0&fields=id,name,description,members,status,type,actualPrice,estimatedPrice,createdAt,updatedAt,details&sort=updatedAt+desc