## What
This (admittedly massive) PR updates the "physical" documentation
structure and fixes url inconsistencies and SEO problems reported by
marketing. The main points are:
- remove or move directories : advanced, user_guide, deploy, api
- move the files contained within to the appropriate one of topics,
how-to, tutorials, or reference
- update internal doc links and product links to the content
- create client-side redirects for all the urls that have changed.
A number of the files have been renamed in small ways to better match
their url and to make them easier to find. Additionally, the top-level
api directory has been moved to /reference/api/legacy/unleash (see the
discussion points section for more on this).
## Why
When moving our doc structure to diataxis a while back, we left the
"physical' files lying where they were, because it didn't matter much to
the new structure. However, that did introduce some inconsistencies with
where you place docs and how we organize them.
There's also the discrepancies in whether urls us underscores or hyphens
(which isn't necessarily the same as their file name), which has been
annoying me for a while, but now has also been raised by marketing as an
issue in terms of SEO.
## Discussion points
The old, hand-written API docs have been moved from /api to
/reference/api/legacy/unleash. There _is_ a /reference/api/unleash
directory, but this is being populated by the OpenAPI plugin, and mixing
those could only cause trouble. However, I'm unsure about putting
/legacy/ in the title, because the API isn't legacy, the docs are. Maybe
we could use another path? Like /old-docs/ or something? I'd appreciate
some input on this.
## What
This PR removes or updates references in the docs to Heroku. Most of the code samples have been replaced with a more generic `unleash.example.com` url, while other references have been removed or updated.
Also removes old OpenAPI files that are out of date and redundant with the new generation.
## Background
Come November and Heroku will no longer offer free deployments of Unleash, so it's about time we remove that claim.
Links to the heroku instance are also outdated because we don't have that instance running anymore.
Finally, the OpenAPI files we do have there are old and static, so they don't match the current reality.
## Commits
* Meta: update ignore file to ignore autogenerated docs
I must've missed the ignore file when looking for patterns.
* docs: delete old openapi file.
This seems to have been a holdover from 2020 and is probably
hand-written. It has been superseded by the new autogenerated OpenAPI docs.
* docs: add notes for heroku changes to the frontend readme and pkg
* docs: remove old openapi article and add redirects to new openapi
* docs: fix link in overview doc: point to GitHub instead of heroku
* docs: update quickstart docs with new heroku details
* docs: remove reference to crashing heroku instance
* docs: remove references to herokuapp in code samples
* docs: add a placeholder comment
* docs: update references for heroku updates
* docs: keep using unleash4 for enterprise
* docs: remove start:heroku script in favor of start:sandbox
* docs: remove 'deploy on heroku button'
Now that it's not free anymore (or won't be very shortly), let's
remove it.
* docs: remove extra newline
