Drop kebab-case configuration notation (#196)

Currently there are two different styles for defining both ldap and oauth configuration in _values.yaml_ file: `camelCase` and `kebab-case`.
Supporting both styles created multiple regressions in the past.

⚠️ BREAKING ⚠️
---------------
These changes completely remove any support for `kebab-case` notation in _values.yaml_ in favor of `camelCase`. Configuration keys must use `camelCase`.
Only exception are Kubernetes resource keys for annotations or labels.

Fixes: #188

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/196
Reviewed-by: luhahn <luhahn@noreply.gitea.io>
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: justusbunsi <justusbunsi@noreply.gitea.io>
Co-committed-by: justusbunsi <justusbunsi@noreply.gitea.io>

templates/gitea/statefulset.yaml

@@ -79,6 +79,7 @@ spec:
               value: /data
             - name: GITEA_TEMP
               value: /tmp/gitea
+            {{- if .Values.gitea.ldap.enabled }}
             {{- if .Values.gitea.ldap.existingSecret }}
             - name: GITEA_LDAP_BIND_DN
               valueFrom:
@@ -92,9 +93,10 @@ spec:
                   name: {{ .Values.gitea.ldap.existingSecret }}
             {{- else }}
             - name: GITEA_LDAP_BIND_DN
-              value: {{ default (index .Values.gitea.ldap "bind-dn") .Values.gitea.ldap.bindDn | quote }}
+              value: {{ .Values.gitea.ldap.bindDn | quote }}
             - name: GITEA_LDAP_PASSWORD
-              value: {{ default (index .Values.gitea.ldap "bind-password") .Values.gitea.ldap.bindPassword | quote }}
+              value: {{ .Values.gitea.ldap.bindPassword | quote }}
+            {{- end }}
             {{- end }}
             {{- if .Values.gitea.admin.existingSecret }}
             - name: GITEA_ADMIN_USERNAME