Created specific directory for oracle cloud

examples/terraform/oracle cloud/connect using ssh to an instance through a bastion/README.md

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+# Oracle Bastion
+
+Simple example to create a Bastion in Oracle Cloud.
+
+1. [Requirements](#requirements)
+2. [SSH configuration](#ssh-configuration)
+3. [Further readings](#further-readings)
+4. [Sources](#sources)
+
+## Requirements
+
+1. VCN
+1. **Private** Subnet
+1. **RSA** SSH key
+
+For a Subnet to be considered Private, it needs to have associated a Route Table with a default route pointing to a NAT Gateway.
+
+> **Note:** NAT Gateways are not included in Oracle's free tier.
+
+The default route table created using Terraform does not contain this route, nor it is possible to create the single route in it at the time of writing.<br />
+A solution to this is to create a new Route Table **with** the default route above and attach it to the Subnet. See the code for details.
+
+![requirements]
+
+## SSH configuration
+
+```ssh_config
+Host  bastion
+  Hostname                  host.bastion.eu-amsterdam-1.oci.oraclecloud.com
+  HostkeyAlgorithms         +ssh-rsa
+  PubkeyAcceptedAlgorithms  +ssh-rsa
+  LocalForward              8022 10.0.0.230:22
+  User                      ocid1.bastionsession.oc1.eu-amsterdam-1.amaaaaaazsnap6iazqwiktq2b7i736d5cgc2vnswuypa3iey754rlj4yyrvq
+
+Host  instance
+  Hostname  localhost
+  User      opc
+  Port      8022
+
+Host  bastion instance
+  IdentityFile           ~/.ssh/id_rsa
+  IdentitiesOnly         yes
+  StrictHostKeyChecking  no
+  UserKnownHostsFile     /dev/null
+```
+
+## Further readings
+
+## Sources
+
+- [Ridiculously powerful free server in the cloud]
+- [Always free resources] in Oracle Cloud
+- [Oracle Cloud Infrastructure Provider documentation]
+- [oracle-terraform-modules/terraform-oci-compute-instance]
+
+<!-- internal references -->
+[requirements]: design/requirements.png
+
+<!-- external references -->
+[always free resources]: https://docs.oracle.com/en-us/iaas/Content/FreeTier/freetier_topic-Always_Free_Resources.htm
+[oracle cloud infrastructure provider documentation]: https://registry.terraform.io/providers/oracle/oci/latest/docs
+[ridiculously powerful free server in the cloud]: https://medium.com/codex/ridiculously-powerful-free-server-in-the-cloud-dd4da8524a9c
+[oracle-terraform-modules/terraform-oci-compute-instance]: https://github.com/oracle-terraform-modules/terraform-oci-compute-instance