chore: Add templates for mongodbatlas_search_deployment

[andreaangiolillo]

Description

Ticket: CLOUDP-221361
This PR adds the templates needed to generate the documentation for the mongodbatlas_search_deployment resource and data source via TFplugindocs. See Spec: Add HashiCorp automation tooling to Terraform development process for more info.

Link to any related issue(s):

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contribution guidelines
• I have checked that this change does not generate any credentials and that they are NOT accidentally logged anywhere.
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code
• If changes include deprecations or removals, I defined an isolated PR with a relevant title as it will be used in the auto-generated changelog.

Further comments

[AgustinBettati]

Should we follow the convention of placing templates within ./templates folder? reference: https://github.com/hashicorp/terraform-plugin-docs?tab=readme-ov-file#conventional-paths.
For this example it would mean placing the file in ./templates/resources/search_deployment.html.markdown.tmpl

[andreaangiolillo]

I don't have a strong opinion here. Updating

[andreaangiolillo]

updated

[AgustinBettati]

LGTM, would just remove the CLOUDP-* reference from the PR title out of convention