fix: sshkeys and project id type and update docs

[ynhummel]

What does this PR do?

This PR aims to solve some know problems with our provider

• The server sshkeys attribute type
• The ServerProject.ID type

Description of Task to be completed?

Update sshkeys and ServerProject.ID type and some general updates to comply with our Go-SDK v0.2.6

How should this be manually tested?

• Installation Before installing you will need to modify the Makefile present in the folder with the right information. Normally you'll only need to modify two fields:

  VERSION=0.0.1 # Make sure this doesn't interfere with other installations that you might have. I leave it as 0.0.1
  OS_ARCH=linux_amd64 # This is your operating system architecture

  You can find the full list of suported OS_ARCH at https://github.com/latitudesh/terraform-provider-latitudesh/releases by expanding Assets.

Them run make install to do a local installation of the provider.

• Setup Create a new folder with a main.tf file:

  
  # main.tf
  terraform {
  required_providers {
  latitudesh = {
    source  = "latitude.sh/iac/latitudesh"
    version = "~> 0.0.1"
  }
  }
  }

Configure the provider

provider "latitudesh" { auth_token = }

and run `terraform init`. Now you are ready to start using terraform.