Bump pulsar version to 2.7.1 (apache#109)

### Motivation

Release with pulsar 2.7.1

### Modification

- update pulsar version from 2.7.0 to 2.7.1
- add a script for updating the pulsar version

Allow use of existing secret for pulsar manager credentials (apache#69)

Signed-off-by: Jiří Pinkava <jiri.pinkava@rossum.ai>

Co-authored-by: Jiri Pinkava <jiri.pinkava@rossum.ai>

Bump Pulsar 2.7.0 (apache#88)

Co-authored-by: Sijie Guo <sijie@apache.org>

Use `.Release.Namespace` by default to handle namespaces (apache#80)

It remains possible to override the current release namespace by setting
the `namespace` value though this may lead to having the helm metadata
and the pulsar components in different namespaces

Fixes apache#66

### Motivation

Trying to deploy the chart in a namespace using the usual helm pattern fails for example
```
kubectl create ns pulsartest
helm upgrade --install pulsar -n pulsartest apache/pulsar
Error: namespaces "pulsar" not found
```
fixing that while keeping the helm metadata and the deployed objects in the same namespace requires declaring the namespace twice 
```
kubectl create ns pulsartest
helm upgrade --install pulsar -n pulsartest apache/pulsar --set namespace=pulsartest
Error: namespaces "pulsar" not found
```
This is needlessly confusing for newcomers who follow the helm documentation and is contrary to helm best practices.

### Modifications

I changed the chart to use the context namespace `.Release.Namespace` by default while preserving the ability to override that by explicitly providing a namespace on the commande line, with the this modification both  examples behave as expected
 
### Verifying this change

- [x] Make sure that the change passes the CI checks.

Bump the image version to 2.6.2 (apache#81)

Signed-off-by: xiaolong.ran <rxl@apache.org>

### Motivation

Bump the image version to 2.6.2

### Verifying this change

- [x] Make sure that the change passes the CI checks.

add support for multiple clusters (apache#60)

Co-authored-by: Elad Dolev <elad@firebolt.io>

### Motivation

Give the ability to deploy multi-cluster instance on K8s clusters with non-default `clusterDomain`, and connect to external configuration-store

### Modifications

- give the ability to change cluster's name
- give the ability to change `clusterDomain`
- fix external configuration store functionality
- use broker ports variables
- use label templates, and add `component` label in several places

### Verifying this change

- [x] Make sure that the change passes the CI checks.

Bump the image version to 2.6.1 (apache#57)

Signed-off-by: xiaolong.ran rxl@apache.org

Motivation
Follow release process and bump the image version to 2.6.1

Fix zookeeper antiaffinity (apache#52)

Fixes apache#39 

### Motivation

The match expression for the "app" label was incorrect breaking the antiaffinity since they would never match. Fixing this makes the podAntiAffinity work, but now requires at least N nodes to be in the cluster where N = largest replica set with affinity. Added the option to set the affinity type to preferredDuringSchedulingIgnoredDuringExecution where it will try to follow the affinity, but will still deploy a pod if it needs to break it. 

### Modifications

- Fixed app matchExpression 
- Added option to set the affinity type 
- bumped chart version

### Verifying this change

- [X] Make sure that the change passes the CI checks.

Fix deprecated values (apache#49)

Fixes apache#46

### Motivation

There were some templates that relied on extra values that are deprecated. 

### Modifications

Modified the checks to check for non deprecated values or deprecated values. 

### Verifying this change

- [X] Make sure that the change passes the CI checks.

Allow Grafana to work with a reverse proxy (apache#48)

### Motivation

Allow Grafana to be served from a sub path.  

### Modifications

- Added a config map to add extra environment variables to the grafana deployment. As the grafana image adds new features that require environment variables, this can be used to set them.
- Bumped the grafana image to allow a reverse proxy
- removed ingress annotations as they are specific to nginx, and to match all the other ingresses
- bumped the chart version as per the README 


Example values:
```
grafana:
  configData:
    GRAFANA_ROOT_URL: /pulsar/grafana
    GRAFANA_SERVE_FROM_SUB_PATH: "true"
  ingress:
      enabled: true
      port: 3000
      path: "/pulsar/grafana/?(.*)"
      annotations:
        nginx.ingress.kubernetes.io/rewrite-target: /$1
```