[FEATURE] Allow context to be set on parameter url

**Is your feature request related to a problem? Please describe.**
Other SDKs allows only paymaster URL to be changed without the ability to set context

**Describe the solution you'd like**
Allow context to be set on the parameter url &context=sponsor &context=erc20&token=USDC

**Describe alternatives you've considered**
-

**Additional context**
- 
