Fix CodeQL note-severity alerts: missing @Override annotations

[vharseko]

Closes all 57 java/missing-override-annotation alerts.

The compiler is the check here: javac rejects @Override on a method which does not override anything, so every one of the 57 annotations is a confirmed override, and the change cannot alter behaviour.

Where they are

• TextHTTPAccessLogPublisher — 18
• SNMP access control lists and MIB tables (SNMPInetAddressAcl, SNMPUserAcl, DsTableEntryImpl, DsApplIfOpsEntryImpl, DsMIBImpl, SNMPMonitor) — 22
• the three PBKDF2 password storage schemes — 12
• OpenDJProvider, SubResourceCollection, SubResourceSingleton, ServiceDiscoveryMechanismConfigManager, WritabilityMode — 5

One special case

In TextHTTPAccessLogPublisher the annotated methods are the bodies of the enumeration constants, written as a single line table under a // @formatter:off marker:

    ELF_C_IP("c-ip")
            { @Override Object valueOf(HTTPRequestInfo i, String tsf) { return i.getClientAddress (); } },

The annotation has to go inside the constant body — placing it above the constant does not compile — and it is kept inline so that the alignment of the 18 line table is preserved.

Testing

• Full suites: opendj-core 8173 tests, opendj-config 547, opendj-rest2ldap 531, opendj-server 3 — all passing.
• opendj-server-legacy (-Pprecommit), covering the annotated classes: PBKDF2PasswordStorageSchemeTestCase (39), PBKDF2HmacSHA256PasswordStorageSchemeTestCase (39), PBKDF2HmacSHA512PasswordStorageSchemeTestCase (39), AbstractTextAccessLogPublisherTest (27), SNMPSyncManagerV2AccessTest (12), DebugLogPublisherTest (6), SNMPTrapManagerTest (1) — 163 tests, all passing.