Revisit security related APIs across all StdLibs

[ldclakmal]

Description
Need to revisit security related APIs such as authn/authz/securesocket etc. across all the StdLibs.

[ldclakmal]

The detailed review of Ballerina security APIs of StdLib protocol connector modules can be found at [1]. All the identified issues are grouped under area/security label [2].

[1] https://docs.google.com/document/d/16r_gjBi7SIqVffKVLtKGBevHQRxp7Fnoo9ELyIWV1BM/edit?usp=sharing
[2] https://github.com/ballerina-platform/ballerina-standard-library/issues?q=is%3Aopen+is%3Aissue+label%3Aarea%2Fsecurity

[ldclakmal]

Reviewed and tested the APIs of HTTP, WebSocket, GraphQL, gRPC, WebSub, NATS, STAN, RabbitMQ, Kafka, Email, FTP, TCP, UDP modules from the security point of view. Here are my observations and recommendations.

• All the issues/bugs/improvements identified are reported and all of them are categorized under the area/security label. Some of them were fixed while completing this task and as of now there are 44 open issues (including 3 bugs).
  https://github.com/ballerina-platform/ballerina-standard-library/issues?q=is%3Aopen+is%3Aissue+label%3Aarea%2Fsecurity
• Section 3.1 of the following doc has a summary of the implementation security APIs of modules and issues have been created for the gaps identified.
  https://docs.google.com/document/d/16r_gjBi7SIqVffKVLtKGBevHQRxp7Fnoo9ELyIWV1BM/edit?usp=sharing
• IMO, the following 15 issues should be prioritized in the first iteration. Module owners can check and update the priority of those.
  https://github.com/ballerina-platform//ballerina-standard-library/issues?q=is%3Aopen+label%3Aarea%2Fsecurity+label%3APriority%2FHigh

Issues breakdown: https://ldclakmal.me/ballerina-security/issues/