Enable NodeFeatureApi in NFD

[wmousa]

…namespace

This patch does the following:

• Set enableNodeFeatureApi to true by default
• Run the NFD with default annotation namespace
• Enhance READE NFD documentation

[e0ne]

Please. re-format this commit message to:

Enable NodeFeatureApi in NFD

This patch does the following:
 - Set enableNodeFeatureApi to true by default
 - Run the NFD with default annotation namespace
 - Enhance README NFD documentation

Signed-off-by: Waleed Mousa <waleedm@nvidia.com>

[e0ne]

LGTM. It could be merged once CI passes

[wmousa]

@adrianchiris
The following was tested:

• Upgrading from the old version of NFD to the new version.
• Deploy the GPU Operator with nfd.enabled=true, then deploy the Network operator with nfd.enabled=false
• Deploy the GPU Operator with nfd.enabled=true, then deploy the Network operator with nfd.enabled=true
• Deploy the Network operator with nfd.enabled=true, then deploy the GPU Operator with nfd.enabled=false
• Deploy the Network operator with nfd.enabled=true, then deploy the GPU Operator with nfd.enabled=true
• Dploy NFD using upstream charts, then, deploy the GPU Operator with nfd.enabled=false, then deploy the Network operator with nfd.enabled=false