feat: add Technitium DNS Home Assistant add-on

- repository.yaml manifest for HA add-on store
- technitium_dns add-on using upstream technitium/dns-server image
- config.yaml with ports 53/udp, 53/tcp, 5380/tcp and password schema
- Dockerfile symlinks /etc/dns to /data/dns for persistent config
- READMEs for repo and add-on

technitium_dns/config.yaml

@@ -0,0 +1,25 @@
+name: Technitium DNS
+version: 1.0.0
+slug: technitium_dns
+description: Technitium DNS Server add-on for Home Assistant
+arch:
+  - amd64
+  - aarch64
+  - armv7
+init: false
+url: https://github.com/technitiumsoftware/dnsserver
+webui: http://[HOST]:[PORT:5380]/
+ports:
+  53/udp: 53
+  53/tcp: 53
+  5380/tcp: 5380
+map:
+  - addon_config:rw
+  - ssl
+options:
+  admin_password: CHANGE_ME
+  timezone: UTC
+schema:
+  admin_password: password
+  timezone: str
+image: technitium/dns-server