Enforce Trampoline constraints

We add a `check_trampoline_constraints` similar to
`check_blinded_path_constraints` that compares the Trampoline onion's amount
and CLTV values to the limitations imposed by the outer onion.

We also add the expected errors by the spec: `TemporaryTrampolineFailure`,
`TrampolineFeeOrExpiryInsufficient` and `UnknownNextTrampoline` to be used
when encountering errors during forwarding or constraint validation.

Finally, we add and modify the following tests:
- Modified the unblinded receive to validate when receiving amount less than
expected
- Modified test with wrong CLTV parameters that now fails with new enforcement
of CLTV limits
- Add unblinded receive test that forces trampoline onion's CLTV to be greater
than the outer onion packet

Note that there are some TODOs to be fixed in following commits as we need
the full trampoline forwarding feature to effectively test all cases.

Co-authored-by: Arik Sosman <[email protected]>

Author: a-mpch