Align rallly chart with repo conventions (batch 3)

- Rename the Deployment (and its labels/selector/pod template/container)
  to {{ .Release.Name }}-{{ .Chart.Name }}-deployment per the naming
  scheme; the Service selector follows.
- Move the hardcoded pod/container security contexts into values
  (rallly.securityContext.pod / .container), defaults unchanged; the
  bogus null entry under capabilities.add becomes an empty list.
- Ingress standard: ingress.className value (default nginx) and
  ingress.annotations merged with the cert-manager annotation;
  domain/clusterIssuer stay required, TLS secret name already conformed.
- Add the tpl-rendered rallly.env value (value/secretKeyRef/
  configMapKeyRef forms), appended to the built-in env.
- Major bump 3.1.2+up4.12.3 -> 4.0.0+up4.12.3 (deployment rename
  replaces the Deployment on upgrade: selector is immutable).

rallly/Chart.yaml

@@ -5,7 +5,7 @@ icon: https://raw.githubusercontent.com/lukevella/rallly/main/apps/landing/publi
 
 type: application
 
-version: 3.1.2+up4.12.3
+version: 4.0.0+up4.12.3
 appVersion: "4.12.3"
 
 maintainers: