doc: add TP#001 for Big Blocks

[Bidon15]

Test Plan covers big blocks epic.
Rendered:

• Test Plan : link to view
• Test Cases are embedded inside the plan

Closes #1 #6
Ref: celestiaorg/celestia-node#7 celestiaorg/celestia-node#602

[Wondertan]

Cool. I like the taken documentation approach.

A few comments:

• Syncing and dasing from the network perspective are the same. What for full Nodes is block syncing for light nodes is block dasing. This means that tc-002 == tc-004 and tc-003 == tc-005. So we can keep -das- cases only for lights and -sync only for fulls(right now, both sync and das cases mention Full/Light node types) or combine equal tests into one.
• There is a lot of common text between tests that feels too repetitive, but this might be just me, and it might a good thing for such test docs.

[Bidon15]

Cool. I like the taken documentation approach.

A few comments:

• Syncing and dasing from the network perspective are the same. What for full Nodes is block syncing for light nodes is block dasing. This means that tc-002 == tc-004 and tc-003 == tc-005. So we can keep -das- cases only for lights and -sync only for fulls(right now, both sync and das cases mention Full/Light node types) or combine equal tests into one.
• There is a lot of common text between tests that feels too repetitive, but this might be just me, and it might a good thing for such test docs.

Thanks for the review!

Ok. Then I'll redo cases tc -> 002 004 003 005 to be specific to either Full or Light

Yes. The general idea of test-case is to as atomic as possible from a description pov. Having dependencies between tests (both execution and text desc) is a bad design choice

[Wondertan]

Great job! Thanks