Update default IOPS and 0.9.0 info guide

[themantissa]

Description

Update default IOPS for AWS which for most M sizes now defaults at 3000 and 0.9.0 info guide for release

Link to any related issue(s):

Type of change:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• [ X] Documentation fix/enhancement

Required Checklist:

• [X ] I have signed the MongoDB CLA
• [ X] I have read the Terraform contribution guidelines
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• [ X] I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code

Further comments

[leofigy]

looks good