Porting to gnolang/gno's examples

[thehowl]

util/gnolanddev/Dockerfile contains a few patches that show what is currently crucially lacking on gnolang/gno to port over the packages and the realm to the monorepo:

• Pull request refactor(gnovm): make IsOriginCall/AssertOriginCall rely on PrevRealm gnolang/gno#1048, otherwise the tests will be failing and trying to use AssertOriginCall with the current system is substantially tricky.
• Completing the strconv stdlib. (Specifically, we need strconv.FormatFloat to print Glicko2's rating values).

After these are done, everything can be ported (probably as a periodical snapshot of this repo's content) over to the examples directory of the monorepo.