feat(api): restore CRD field descriptions for operator-owned types

[Sanil2108]

Summary

Restores CRD field descriptions that were removed in #2703 to keep CRD sizes manageable.

• Sets maxDescLen=128 (previously maxDescLen=0) in the controller-gen CRD generation options, restoring truncated but meaningful descriptions for all operator-defined fields
• Updates the make install target to use kubectl apply --server-side to support the larger CRD payloads

Background

PR #2703 set maxDescLen=0 because kubectl apply -f crd-file.yaml was failing due to CRD size. This removed all field descriptions from the generated CRDs, making kubectl explain and API documentation less useful.

With maxDescLen=128, the largest CRD (OpenTelemetryCollectors) grows from ~400KB to ~900KB, which is within etcd's object size limits. Using --server-side apply avoids the last-applied-configuration annotation that doubles the payload for client-side apply.

CRD sizes with this change

CRD	Before (maxDescLen=0)	After (maxDescLen=128)
opentelemetrycollectors	405KB	900KB
targetallocators	153KB	346KB
instrumentations	92KB	185KB
opampbridges	73KB	166KB
clusterobservabilities	5KB	11KB

Example

Before:

configVersions:
  default: 3
  minimum: 1
  type: integer

After:

configVersions:
  default: 3
  description: ConfigVersions defines the number versions to keep for
    the collector config. Each config version is stored in a separate ConfigMap.
  minimum: 1
  type: integer

Resolves: #2737

Test plan

• make manifests regenerates CRDs with descriptions present
• Verified kubectl explain shows field descriptions for operator-owned types
• CRD sizes verified to be within etcd object size limits

[iblancasa]

I'm not against enabling this again but only if we have some kind of test that probes the operator is not broken because of this.

[swiatekm]

I'm not sure we want to do this. Or at least not until we drop support for v1alpha1 Collectors.