Update the jwt signing to be compliant with jjwt 0.12.6

[R-Sandor]

Details

The latest version of JJWT require that JWTs be signed with a supported key and now any encryption method. Despite a somewhat wide adoption of people signing JWTs with an RSA key the library has made the user of the library do more leg work.

• https://github.com/R-Sandor/FindFirst/blob/e79905f34d2162bcbb1250733a34d9bb41878172/server/build.gradle#L103

Tasks

• Ensure that all integration test are passing upon making the change, everything should pass.
• Update JWT service and any encoding and decoding function.
• Provide a summary as to why certain changes were made, this is not normally required but given it has a security impact its a requirement.

[reetikg]

Hi, I'd like to work on this issue. Please assign it to me.

[R-Sandor]

@reetikg Thanks! All yours :)