support authentication methods other than username/password

[rursprung]

the first version (#25) only introduces username/password authentication (easiest to implement & test), however opensearch offers various other authentication options (see the documentation) and we should support all of them eventually.

this issue should be used to define how this should be implemented and either do it directly for all of them (unlikely) or raise follow-up issues for the different authentication options to be implemented later on (with a clear way forward for them).

[reta]

At the moment, we provide HttpClientConfigCallback / HttpAsyncClientBuilder to allow configuring any aspect of the underlying client(s), including other authentication methods if supported. My concern regarding baking everything into the client itself is that it may not be practical - there are tons of different LDAP / SAML / OpenID / OAuth / JWT / ... libraries there, we cannot support all nor force to use one.

[rursprung]

e.g. for JWT support we need to be able to register an HttpRequestInterceptor here:

liquibase-opensearch/src/main/java/liquibase/ext/opensearch/database/OpenSearchConnection.java

Line 165 in 3fd69aa

return httpClientBuilder

@filipelautert: what would be the canonical way to attach random things at runtime here? the liquibase API seems to be largely based on string-based configuration and not using injection, i.e. i can't just use the spring-way of injecting things, defining defaults in their absence, etc.