feat: improve the LDAP implementation (#615)

* feat(logging): add PV_LOG_LEVEL environment variable to set backend log level

* feat(ldap): Adding a more verbose logging output to debug LDAP issues

* fix(ldap): fixed user logins with special characters within the users dn by switching to ldapts

* feat(ldap): made the member of and email attribute names configurable

* fix(ldap): properly handle email like usernames and fixing #601

* Revert "fix: disable email login if ldap is enabled"

This reverts commit d9cfe697d6.

* feat(ldap): disable the ability for a user to change his email when it's a LDAP user

* feat(ldap): relaxed username pattern by allowing the @ character in usernames

backend/prisma/seed/config.seed.ts

@@ -178,6 +178,15 @@ const configVariables: ConfigVariables = {
     adminGroups: {
       type: "string",
       defaultValue: ""
+    },
+
+    fieldNameMemberOf: {
+      type: "string",
+      defaultValue: "memberOf",
+    },
+    fieldNameEmail: {
+      type: "string",
+      defaultValue: "userPrincipalName",
     }
   },
   oauth: {