* - make immediate nonce-too-low error abort send (since it could never succeed otherwise)

- make txmgr resubmit a transaction when fee bumping fails in case it has been dropped from the mempool

- only bump fees when they really should be bumped

- set txmgr overall default send timeout of 10 minutes. It was infinite, which led to permanently
  stuck transaction in combination with the other bugs fixed in this PR.

* Update op-service/txmgr/txmgr_test.go

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Co-authored-by: Sebastian Stammler <stammler.s@gmail.com>