Consider packing GraalVM CE with Ballerina

[heshanpadmasiri]

Description:
$subject

Describe your problem(s)
Currently users need to manually install GraalVM and set (and probably unset afterward) JAVA_HOME and GRAAL_HOME variables in order to use --graalvm.

Describe your solution(s)
Similar to how we already pack JVM it may make things more convenient for users if we pack GraalVM with ballerina. We can point to the packed GraalVM by default and allow advance users to override this.

Potential problems

1. Not entirely sure if we can pack GraalVM CE due to licensing
2. native-image tool also need the local tool chain (ref). Not sure these are installed by default in most user machines or we need to somehow pack them as well.
3. This could significantly increase the download and install sizes