separate block builder functionality from BABE session

[noot]

Expected Behavior

• the block building functionality (ie lib/babe/build.go) should be separated into a separate submodule
• this will make testing easier for other packages that need to build blocks, but don't need an entire BABE session

Current Behavior

• block building requires a BABE session

Possible Solution

• create a new BlockBuilder type that implements the functions in lib/babe/build.go

Checklist

• I have read CONTRIBUTING and CODE_OF_CONDUCT
• I have provided as much information as possible and necessary
• I am planning to submit a pull request to fix this issue myself

[danigomez]

Hello everyone!
I found this project while reading the Polkadot documentation and i found it very interesting!
I want to start working on this, but i'm not sure if this is still necessary, reviewing the code i found that the BuildBlock method was being used in the test file dot/core/syncer_test.gobut it seems that it doesn't exists anymore.
Am i missing something?
Thanks!

[noot]

@danigomez hi, for this issue you would only need to modify the lib/babe package to create a separate blockBuilder type or such that has the functions used for block building (lib/babe/build.go) defined on it. the babe Service can then use this blockBuilder to build a block. let me know if you need more clarification!

[danigomez]

@noot Ok!, i will start working on this then.