We currently have a specific REST action to retrieve all aliaes, which
uses internally the get index API. This doesn't seem to be required
anymore though as the existing RestGetAliaesAction could as well take
the requests with no indices and aliases specified.
This commit removes the RestGetAllAliasesAction in favour of using
RestGetAliasesAction also for requests that don't specify indices nor
aliases. Similar to #31129.
The core REST tests with security currently use a hardcoded username and
password. This is not amenable to running these tests in scenarios where
the user controls the creation of the cluster and owns the credentials
for this cluster. This commit enables running the core REST tests with
security with a custom username and password.
This commit makes x-pack a module and adds it to the default
distrubtion. It also creates distributions for zip, tar, deb and rpm
which contain only oss code.