docs: Adding link to one-click installation template

[cosark]

Giving community access to one-click deploy template on RepoCloud marketplace for affordable self hosting

[mattermost-build]

Hello @cosark,

Thanks for your pull request! A Core Committer will review your pull request soon. For code contributions, you can learn more about the review process here.

Per the Mattermost Contribution Guide, we need to add you to the list of approved contributors for the Mattermost project.

Please help complete the Mattermost contribution license agreement? Once you have signed the CLA, please comment with /check-cla and confirm that the CLA check is green.

This is a standard procedure for many open source projects.

Please let us know if you have any questions.

We are very happy to have you join our growing community! If you're not yet a member, please consider joining our Contributors community channel to meet other contributors and discuss new opportunities with the core team.

[mattermost-build]

This PR has been automatically labelled "stale" because it hasn't had recent activity. A core team member will check in on the status of the PR to help with questions. Thank you for your contribution!

[cosark]

Form filled out / ready to merge

[cosark]

Signed 👍