This is an initiative to ensure all documentation complies completely
with the Documentation Style Guide section "Documentation is the single
source of truth (SSOT)" according to this epic
https://gitlab.com/groups/gitlab-org/-/epics/1280.

In particular, the changes of this commit touch all files under
doc/install/. Most notably:

- install/redis.md:
        Redirect to Redis section of install guide.

- install/pivotal/index.md:
        Changed its content to reflect the current status, which is no
        longer supported (since 2017!).

- install/google-protobuf.md:
        Incorporated inside installation.md under the troubleshooting section.

- install/openshift_and_gitlab.md:
        Clarified that this guide is no longer relevant. We might want to
        redirect to the Chart docs in the future.

- install/structure.md:
        Incorporated inside installation.md under its own section.

- install/kubernetes/index.md:
        Redirected to https://docs.gitlab.com/charts

[9.5] Disallow the `name` attribute on all user-provided markup

See merge request gitlab/gitlabhq!2166

[ci skip]

[ci skip]

[ci skip]

We didn't specify that the db user needs the right to create
temporary tables before.
That's why the migration will fail on most installations.
This commits removes the "TEMPORARY" from the migration
and changes the documentation to include the necessary rights for the future.

Make formatting consistent on page.

Change table -> database as they are database permissions.

When looking up the granted permissions for users in MySQL using `show grants for 'git'@'localhost';` it shows the permissions in this order regardless of how you enter them. Changing so that comparing your actual permissions vs. what installation guide says is easier.