Replace legacy OAuth 1.0a

[justaugustus]

From https://developer.atlassian.com/cloud/jira/platform/jira-rest-api-oauth-authentication/:

OAuth 1.0a is a legacy authentication method and, therefore, isn't recommended. Instead, check out the following for details of the recommended authentication approaches for:

Forge apps, see Security for Forge apps.
Connect apps, see Security for Connect apps.
Connect apps that act on behalf of the user, see User impersonation for Connect apps.
Non-Connect apps created in the developer console, see OAuth 2.0 (3LO) apps.
Simple scripts or to make REST API calls yourself, see Basic auth for REST APIs.

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[rappizs]

Forge apps, see Security for Forge apps.
Connect apps, see Security for Connect apps.
Connect apps that act on behalf of the user, see User impersonation for Connect apps.
Non-Connect apps created in the developer console, see OAuth 2.0 (3LO) apps.
Simple scripts or to make REST API calls yourself, see Basic auth for REST APIs.

Based on this, in my opinion, we should only support Basic auth for REST APIs as this is the go to method for simple scripts and REST API calls.