Add subnet-id usability, resource tag support, and PBF function create support to Fn CLI

[Jaytee-fn]

This PR extends Fn CLI with additional OCI Functions usability support for:

• application subnet configuration via a dedicated --subnet-id flag
• user-friendly freeform and defined resource tag flags for applications and functions
• minimal Pre-Built Function (PBF) source-details support for function creation

The change includes -

Application subnet usability

• add 'fn create app --subnet-id'
• map subnet IDs to 'oracle.com/oci/subnetIds'
• validate app creation requires subnet IDs
• return a clear unsupported message for 'fn update app --subnet-id'

Resource tags support

• add freeform tag support:

  • --tag key=value

• add defined tag support:

  • --defined-tag namespace.key=value

• add update helpers:

  • --remove-tag
  • --remove-defined-tag
  • --clear-tags
  • --clear-freeform-tags
  • --clear-defined-tags

• support tags for:

  • fn create app
  • fn update app
  • fn create function
  • fn update function
  • fn init

• persist function tag settings to func.yaml under:

  • deploy.oci.freeform_tags
  • deploy.oci.defined_tags

• map tag settings through the Oracle shim to OCI freeformTags / definedTags

• preserve correct clear/remove semantics for defined/freeform tags

• treat plain defined-tag values as strings by default

  • e.g. --defined-tag dry_run_tag.example-tag=10

• still allow expplicit JSON-style values when needed

PBF source-details support

• add 'fn create function ... --pbf '
• enforce mutual exclusion between '--image' and '--pbf'
• make the positional image argument optional for the PBF create flow
• map '--pbf' to OCI 'sourceDetails' using 'PRE_BUILT_FUNCTIONS'
• automatically resolve the minimum required memory from the current PBF version
• validate user-supplied memory against PBF minimum requirement