docs: add README files for pipelinerun and taskrun examples

[anirudh242]

Changes

Adds README files to the examples/v1/pipelineruns and examples/v1/taskruns directories to help newcomers understand and navigate the example YAML files.

The README files include:

• a brief overview of the examples

• categorized lists of the YAML files

• instructions on how to run the examples

• prerequisites for running Tekton Pipeline and TaskRun examples

Closes #9501

Submitter Checklist

As the author of this PR, please check off the items in this checklist:

• Has Docs if any changes are user facing, including updates to minimum requirements e.g. Kubernetes version bumps
• Has Tests included if any functionality added or changed
• pre-commit Passed
• Follows the commit message standard
• Meets the Tekton contributor standards (including functionality, content, code)
• Has a kind label. You can add one by adding a comment on this PR that contains /kind <type>. Valid types are bug, cleanup, design, documentation, feature, flake, misc, question, tep
• Release notes block below has been updated with any user facing changes (API changes, bug fixes, changes requiring upgrade notices or deprecation warnings). See some examples of good release notes.
• Release notes contains the string "action required" if the change requires additional action from users switching to the new release

Release Notes

NONE

/kind documentation

[tekton-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
To complete the pull request process, please assign pritidesai after the PR has been reviewed.
You can assign the PR to them by writing /assign @pritidesai in a comment when ready.

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

Details

Needs approval from an approver in each of these files:

• OWNERS

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

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: anirudh242 / name: Anirudh Bhardwaj (00fa860)

[anirudh242]

/assign @pritidesai