✨ feat(infrastructure): introduce ansible deployment for taler services

- add ansible playbooks and roles for deploying taler exchange and merchant
- configure PostgreSQL, GNU Taler repositories, and services

🔧 chore(config): provide example env and gitignore for sensitive files

- create .env-example with placeholders for sensitive info
- add .gitignore entries for .env and common editor files

roles/taler_merchant/templates/merchant.conf.j2

@@ -0,0 +1,25 @@
+# Generated by Ansible - manual edits will be overwritten.
+[merchant]
+SERVE = UNIX
+UNIXPATH = /run/taler/merchant.socket
+BIND_TO = 127.0.0.1
+PORT = 9966
+DATABASE = postgres
+UNIXPATH_MODE = 0660
+
+{% set merchant_user = taler_config.db.merchant.user %}
+{% set merchant_pass = taler_config.db.merchant.password %}
+{% set merchant_auth = merchant_user if not merchant_pass else merchant_user ~ ':' ~ merchant_pass %}
+[merchantdb-postgres]
+CONFIG = postgres://{{ merchant_auth }}@{{ taler_config.db.host }}:{{ taler_config.db.port }}/{{ taler_config.db.merchant.name }}
+
+[merchant-exchange-{{ taler_config.currency | lower }}]
+MASTER_KEY = {{ taler_config.exchange_master_key }}
+EXCHANGE_BASE_URLS = https://{{ taler_config.exchange_host }}/
+CURRENCY = {{ taler_config.currency }}
+
+[instance-default]
+MERCHANT_NAME = Demogeld Shop
+PAYTO_URI = payto://x-taler-merchant/{{ taler_config.merchant_host | default(taler_config.exchange_host) }}/demogeld
+DEFAULT_WIRE_TRANSFER_DELAY = 1 day
+DEFAULT_MAX_DEPOSIT_FEE = 0