fix(conf): declare MinIO users in ha/trio template

[Mosney]

The ha/trio template enables MinIO as the pgBackRest repository but does not declare minio_users. When configure -g is used, the S3User.Backup value in pgbackrest_repo is randomized while the MinIO user continues to inherit the default secret from the role.

Declare the default MinIO users explicitly so generated credentials remain consistent.

Problem

The ha/trio template deploys MinIO and enables it as the pgBackRest
repository, but it does not explicitly declare minio_users.

When generating the configuration with:

./configure -c ha/trio -g -s

configure -g replaces S3User.Backup in:

pgbackrest_repo.minio.s3_key_secret

However, minio_users is absent from the generated configuration, so
the MinIO role continues to use its default S3User.Backup secret.

This results in different credentials being used by MinIO and
pgBackRest, causing:

HTTP 403 Forbidden
SignatureDoesNotMatch

during pgbackrest stanza-create.

Root cause

Password generation performs string replacement only on values present
in the selected configuration template. The ha/trio template contains
the pgBackRest S3 secret but not the corresponding MinIO user definition.

Fix

Explicitly declare the standard MinIO users in the ha/trio template,
following the same pattern used by other templates that enable MinIO
backups.

This allows configure -g to replace both the MinIO user secret and the
pgBackRest S3 secret with the same generated value.

[Vonng]

Thanks for catching this and providing a focused fix. This keeps the generated MinIO and pgBackRest credentials consistent in the ha/trio template. Merged—much appreciated!