Add support for Bitwarden Secret Manager EU vaults

[frenkel]

Currently it is not possible to override the Bitwarden Security Manager server url on a case by case basis. You can only do this through the global config. This PR fixes that by adding a new --server-url= argument to the kamal secrets command.

It has touched quite some files because these functions had all the optional arguments named. I've replaced the ones that were not used with ** so any future additions can have a smaller diff.

Fixes https://github.com/basecamp/kamal/discussions/1577.

I'll open a PR for the documentation repo in a few minutes.

[dawidof]

no need you can do in secrets:

SECRETS_RAW=$(kamal secrets fetch --adapter bitwarden-sm <PROJECT_ID>/all)

DATABASE_URL=$(kamal secrets extract DATABASE_URL ${SECRETS_RAW})
SECRET_KEY_BASE=$(kamal secrets extract SECRET_KEY_BASE ${SECRETS_RAW})