Replace the Package.md and Module.md files with README.md File

[ThisaruGuruge]

Description:

The Ballerina Libraries should use the README.md file instead of Package.md and Module.md files going forward. This should be done for the packages that should be released with the Ballerina SwanLake Update 10.

Refer this issue: ballerina-platform/ballerina-lang#42981

[ayeshLK]

As the original PR has been reverted [1] we will have to wait before working on this.

[1] - ballerina-platform/ballerina-lang#43218

[ThisaruGuruge]

Closing the issue since this is not deferred from Update 10.