Confluence/Jira roles: add READMEs, switch to custom images, proxy/JVM envs, and integer-safe heap sizing

Confluence: README added; demo disables OIDC/LDAP; Dockerfile overlay; docker-compose now uses CONFLUENCE_CUSTOM_IMAGE and DB depends include; env.j2 adds ATL_* and JVM_*; vars use integer math (//) for Xmx/Xms and expose CUSTOM_IMAGE.

Jira: initial role skeleton with README, config/meta/tasks; Dockerfile overlay; docker-compose using JIRA_CUSTOM_IMAGE and DB depends include; env.j2 with proxy + JVM envs; vars with integer-safe memory sizing.

Context: https://chatgpt.com/share/68b6b592-2250-800f-b68e-b37ae98dbe70

roles/web-app-confluence/config/main.yml

@@ -15,7 +15,8 @@ features:
   desktop:          true
   central_database: true
   logout:           true
-  oidc:             true
+  oidc:             false # Not enabled for demo version
+  ldap:             false # Not enabled for demo version
 server:
   csp:
     whitelist:      {}