Improve CRD documention

[henrybear327]

What would you like to be added?

Proper documentation for each of the fields in all of the CRD.

Why is this needed?

Let's take the documentation for PrefixClaim as an example.

As we can see, a lot of fields have <no description> as it's documentation, which is not ideal.

➜  netbox-operator-henry git:(feat/issue_79) ✗ kubectl explain prefixclaim.spec
GROUP:      netbox.dev
KIND:       PrefixClaim
VERSION:    v1

FIELD: spec <Object>


DESCRIPTION:
    PrefixClaimSpec defines the desired state of PrefixClaim
    TODO: The reason for using a workaround please see
    https://github.com/netbox-community/netbox-operator/pull/90#issuecomment-2402112475
    
FIELDS:
  comments      <string>
    <no description>

  customFields  <map[string]string>
    <no description>

  description   <string>
    <no description>

  parentPrefix  <string>
    <no description>

  parentPrefixSelector  <map[string]string>
    The `parentPrefixSelector` is a key-value map, where all the entries are of
    data type `<string-string>`.
    The map contains a set of query conditions for selecting a set of prefixes
    that can be used as the parent prefix.
    The query conditions will be chained by the AND operator, and exact match of
    the keys and values will be performed.

  prefixLength  <string> -required-
    <no description>

  preserveInNetbox      <boolean>
    <no description>

  site  <string>
    Use the `name` value instead of the `slug` value

  tenant        <string>
    Use the `name` value instead of the `slug` value