Combining useful information from EKS User Guide.

Moved considerations, prereqs, and IAM steps from EKS User Guide. Globally replaced "EFS" and "AWS EFS" with "Amazon EFS".

"Amazon EKS" branding

Globally replaced "EKS" with "Amazon EKS".

Replacement correction.

Global replacement fix.

Updated links to work with move

Merged deploy/install info from EKS User Guide.

Moved IAM policy steps to separate file.

Removed steps that were moved to separate file.

Added new link.

Moved over "Create an Amazon EFS file system" from user guide

Update and rename efs-create-filesystem to efs-create-filesystem.md

Update iam-policy-create.md

Give extra context.

Adding references to other sections, other tweaks

small edits

Update iam-policy-create.md

Update README.md

Merged extra details from EKS User Guide.

Update README.md

Formatting fixes

Update README.md

Cleaned up descriptions of settings.

Update README.md

Update README.md

Merged extra details from EKS User Guide.

Update README.md

Addressed Ashley's comment regarding numbering starting over. Also updated replacing release-X.X with more clear instructions on how to look up latest active branch.

Corrected Branches links.

Removed mention that master isn't recommended.

I originally added these statements based on my understanding from a different storage driver (https://github.com/kubernetes-sigs/aws-fsx-csi-driver/blob/master/docs/install.md), but this same recommendation may not apply to EFS CSI.