Helm - Templatable host for gateway ingress/route

[Itaykal]

Currently the host value for ingress/route objects for the gateway is not templatable which caused (in my case) to find a workaround for injecting that information using an external tool (ArgoCD did the job for me).
My suggestion is to just do what's already done for grafana/grafana and grafana/agent.

The following lines should be modified:

mimir/operations/helm/charts/mimir-distributed/templates/gateway/gateway-route.yaml

Line 14 in 7306747

host: {{ .Values.gateway.route.host }}

mimir/operations/helm/charts/mimir-distributed/templates/gateway/gateway-ingress.yaml

Line 31 in 7306747

- host: {{ .host | quote }}