Hi @sameryadav,
First of all your requirement, to use AEM as Oauth token is seems to be not good. So you need to update it.
Since AEM is a CMS tool to keep it like that only, So What can you do in your requirement is simply create some OSGI configuration to configure client_id, client_secret and fallback_urls etc. then while making a call to salesforce use those fields for authorisation.
I think salesforce has rich support for Rest API Authorisation.
Please see the below URL:
https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/quickstart_oauth.htm
Hope this will help.
Umesh Thakur