Rename GetPlatform functions to not reflect implementation

[ykaliuta]

GetReleaseFromCSV name is more about implementation than the task it
performs. The function fetches actual running operator release and
CSV is only one possibility for that.

GetReleaseFromCR name is more about implementation than the task it
performs. The function fetches release from DSC/DSCI mean the latest
release the data science cluster was deployed by. Consider it as
"deployed release".

Description

How Has This Been Tested?

Screenshot or short clip

Merge criteria

• You have read the contributors guide.
• Commit messages are meaningful - have a clear and concise summary and detailed explanation of what was changed and why.
• Pull Request contains a description of the solution, a link to the JIRA issue, and to any dependent or related Pull Request.
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has manually tested the changes and verified that the changes work

[ykaliuta]

/cc @zdtsw @lburgazzoli

[ykaliuta]

/test opendatahub-operator-e2e

[openshift-ci]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lburgazzoli, zdtsw

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [lburgazzoli,zdtsw]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment