Docs : Adding Step by Step Plugin Example with Code explanation

[SiddheshKukade]

This Issue is associated with Google Summer of Code 2022 Project link

Is your feature request related to a problem? Please describe.
Adding Step by Step Plugin Example with Code explanation
Recently Plugin Architecture is implemented in talawa repositories with Plugin store on the admin. A detailed step by step example must be created to showcase the process of conversion of existing feature as a plugin.

Describe the solution you'd like

• Technical overview of the steps used to convert the features into pluigns [GSOC]Docs : Adding Step by Step Plugin Example with Code explanation #256
• Step-by-step example of actual conversion of a feature to a plugin (ex. Donation feature) [GSOC] Docs : Adding Step by Step Plugin Example  #258

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Approach to be followed (optional)
Add the docs by explaining the plugin architecture example

[SiddheshKukade]

@palisadoes sir I would like to work on this issue.