[DPE-8381] Add docs tmpfs warning

[marceloneppel]

Issue

We're fixing the tmpfs mount and using it for the temp storage after a reboot on canonical/postgresql-single-kernel-library#11 and #1156.

However, there is nothing documented regarding that only the charm supports the tmpfs storage provider only for the temp storage (and not for the archive, data, and logs storage).

Solution

Add a warning in the documentation.

Checklist

• I have added or updated any relevant documentation.
• I have cleaned any remaining cloud resources from my accounts.

[a-velasco]

Thank you @marcelo! Made some small suggestions.

One last tiny request: could you remove the leftover " symbol after the word latest on line 7? (another typo that already existed before this PR). For some reason, the GitHub interface doesn't let me comment on that line after expanding the file.

[a-velasco]

Regarding the CI errors:

• charmhub.io 500 error -> known issue, should not block merging
• juju anchor issues -> they've changed their headings lately, so we need to update the links with the new anchors
• terraform.io error -> known issue due to their new CDN protections rejecting our GH runners, should not block merging

[marceloneppel]

Thank you @marcelo! Made some small suggestions.

One last tiny request: could you remove the leftover " symbol after the word latest on line 7? (another typo that already existed before this PR). For some reason, the GitHub interface doesn't let me comment on that line after expanding the file.

Sure! Thanks for noticing that. I removed that on 0b369be.

I'm now updating the Juju anchors.

[marceloneppel]

Regarding the CI errors:

• charmhub.io 500 error -> known issue, should not block merging
• juju anchor issues -> they've changed their headings lately, so we need to update the links with the new anchors
• terraform.io error -> known issue due to their new CDN protections rejecting our GH runners, should not block merging

Thanks! I fixed the Juju anchors on 316720c.

[a-velasco]

Thanks @marceloneppel!