Implement the findroute, findroutetonode and findroutebetweennodes commands

[mohitk108]

The implementations of these commands are added through this PR.
Code for autocompletion and unit tests, for the respective commands are also added.
To see the documentation of these commands, kindly refer : API Documentation

[t-bast]

You're only testing the case where format=nodeId, you need to also test the format=shortChannelId and format=full cases.

[mohitk108]

Yes, I'll cover them soon.

[mohitk108]

I've added the test for different cases, like format=nodeId and sshortChannelId as well in 9f6f5fa for the findroute command.
The build will fail right now, since I've modified the EclairClientMocks. I will update the remaining tests once you approve this particular change.
You can individually run the test right now. It's passing for me.

[t-bast]

I will update the remaining tests once you approve this particular change.

I'm not sure what particular change you want me to review before finishing the work?
You should simply finish updating the tests and then I'll be able to review it?