Increase the default resource memory requirement for Repo Server.

[iam-veeramalla]

Describe the bug
From v1.2, All the Argo CD workloads in the default Instance namespace are deployed with resource requests/limits by default. The current resource requests and limits set on the repo server is:

Requests: v1.ResourceList{
	Memory: "256Mi",
        CPU:   "250m",
},
Limits: 
       Memory: "512Mi",
       CPU:    "1000m",

However, many users have reported OOM issues on the repo-server. Looking at the issues I think we would need to upgrade the memory from 512Mi to 1024Mi

To Reproduce
Steps to reproduce the behavior:

1. run the operator from the console or from the CLI using operator-sdk run local
2. Move to Workloads -> Deployment -> openshift-gitops-repo-server and look at the memory limit that is set.

Expected behavior
OOM crash should be avoided.

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Additional context
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