Deprecate SpringSecurityLdapTemplate

[jzheaux]

SpringSecurityLdapTemplate exposes many operations that are available in modern-day Spring LDAP by way of LdapClient and LdapQueryBuilder. We should try and replace usage of SpringSecurityLdapTemplate with Spring LDAP's default LdapClient implementation to simplify maintenance and configuration.

• Change PasswordComparisonAuthenticator to use LdapClient #17289
• Change FilterBasedLdapUserSearch to use LdapClient #17290
• Change ActiveDirectoryLdapAuthenticationProvider to use LdapClient #17291
• Add an LdapAuthoritiesPopulator implementation that uses LdapClient
• Deprecate SpringSecurityLdapTemplate

[minkukjo]

@jzheaux
I would like to work on this issue.
Please let me know if it's available for contribution.
Thanks!

[jzheaux]

Thanks, @minkukjo! I've converted the first three to issues and we can start from there. If you would please comment on one of those and I'll assign it to you.