oauth2-client: migrate apps to use oauth2-client helm chart (#90)

* headscale: use oauth2-client helm chart

* pihole: use oauth2-client helm chart

* matrix: use oauth2-client helm chart

* oauth2: pass issuer address to pihole, headscale and matrix apps

* pihole: fix secret name

* matrix: fix version to v1.98.0

* headscale: make oauth2-client depend on auth release

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Co-authored-by: Giorgi Lekveishvili <lekva@gl-mbp-m1-max.local>
diff --git a/charts/headscale/values.yaml b/charts/headscale/values.yaml
index 6152794..18d7b57 100644
--- a/charts/headscale/values.yaml
+++ b/charts/headscale/values.yaml
@@ -8,11 +8,10 @@
 certificateIssuer: lekva-public
 domain: headscale.example.com
 publicBaseDomain: example.com
-oauth2:
-  hydraAdmin: http://hydra-admin
-  hydraPublic: https://hydra.example.com
-  secretName: oauth2-client-headscale
 ipAddressPool: example-headscale
+oauth2:
+  secretName: oauth2-client
+  issuer: https://oidc-issuer.example.com
 api:
   port: 8585
   ipSubnet: 10.1.0.0/24