Add a new node role `cluster_manager`, as the replacement for `master` role, that used in setting `node.roles: [ master ]`.
They have got the same functionality, but can NOT be assigned to `node.roles` together.
* Add `CLUSTER_MANAGER_ROLE` in `DiscoveryNodeRole` class, and deprecate `MASTER_ROLE`
* Remove `MASTER_ROLE` from the `DiscoveryNodeRole.BUILT_IN_ROLES`, and temporarily load the role by the existing method `DiscoveryNode.setAdditionalRoles`
* Add a method `validateRole()` in `DiscoveryNodeRole` class, it's used to validate a specific role is compatible with the other roles to be assigned to a node together.
* Add deprecation message when assigning `master` role in setting `node.roles`
* Replace most `MASTER_ROLE` with `CLUSTER_MANAGER_ROLE` in current unit and integration tests
* Add new unit and integration tests to validate `CLUSTER_MANAGER_ROLE` and `MASTER_ROLE` can be treated as the same.
More explanation:
* New node will have "cluster_manager", "data", and "ingest" roles by default. Which means the default value of setting "node.roles" will be `["cluster_manager","data","ingest"]`, instead of `["master","data","ingest"]`
* "cluster_manager" role will be treated as "master" role in the OpenSearch node of previous versions.
* "cluster_manager” role and "master" role have got the same abbreviation name: "m"
Signed-off-by: Tianli Feng <ftianli@amazon.com>
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