CLOUDP-245948: Rename openapicli to foascli

[andreaangiolillo]

Proposed changes

Jira ticket: CLOUDP-245948

Rename the openapicli to foascli.

./bin/foascli --version                                                                                                                                                  
foascli version: v0.0.1
git version: 9e33ea2d8aa10e7331d31e3a71b440654ad85a12
Go version: go1.22.1
   os: darwin
   arch: arm64
   compiler: gc

./bin/foascli merge --help                                                                                                                                         
Merge Open API specifications into a base spec.

Usage:
  foascli merge -b base-spec [-e spec]... [flags]

Flags:
  -b, --base string            Base OAS. The command will merge other OASes into it.
  -e, --external stringArray   OASes that will be merged into the base OAS.
  -h, --help                   help for merge
  -o, --output string          File name where the command will store the output. (default "FOAS.json")

Checklist

• I have signed the MongoDB CLA
• I have added tests that prove my fix is effective or that my feature works

Further comments