Follow up items for #3019

[crodriguezvega]

Once #3019 is merged, these items will be worked on in a follow-up PR:

• Write documentation (docs & migration) (transfer (total escrow): add documentation and migration docs #3509)
• Fix base transfer e2e test (Fix escrow proto E2E #3517).
• Fix upgrade e2e test and make sure it passes (e2e: conditionally query total escrow based on release version #3605).
• As recommended by @colin-axner, add invariants to check that actual amounts are equal or greater than the expected escrow amount. (transfer (total escrow): add invariant for total escrow #3506)
• Apply this suggestion. (transfer (total escrow): add escrow / unescrow functions #3507)
• Add ADR and link in the code to the ADR. I think this should not block the release of the feature, though, and we can add it afterwards. (docs: adr 011 total escrow state entry #3641)
• add link in migration docs once backport is merged (see TODO)

[crodriguezvega]

Closed by #3558