[Blocker v10] Redirect old doc links

[sidharthv96]

Description

There will be tons of links to mermaid docs across various sites.
We should figure out a way to redirect the old URL's to new ones.

Steps to reproduce

eg: mermaid-js/mermaid-live-editor#1076

Although this is a different issue, it's still relevant.

PS @emersonbottero

[fkohrt]

Just stumbled over the following broken link and thought it might be relevant for this issue:

mermaid/packages/mermaid/src/docs/community/development.md

Line 9 in c8b377b

**The Docs Structure is dictated by [sidebar.md](https://github.com/mermaid-js/mermaid/edit/develop/src/docs/_sidebar.md)**

The rendered documentation page containing the broken link is here.

[spier]

It doesn't solve the issue of possibly having to redirect old URLs so that inbound links keep working.

However I have fixed some of the broken links, including the example provided by @fkohrt, as part of #3765.

[sidharthv96]

8.6.0_docs
Setup
Tutorials
accessibility
breakingChanges
c4c
classDiagram
configuration
cover
custom-navbar
demos
development
directives
entityRelationshipDiagram
examples
faq
flowchart
gantt
gitgraph
https://mermaid-js.github.io/mermaid/#/./Tutorials
https://mermaid-js.github.io/mermaid/#/./integrations
https://mermaid-js.github.io/mermaid/#/flowchart?id=special-characters-that-break-syntax
https://mermaid-js.github.io/mermaid/#/n00b-gettingStarted?id=_3-calling-the-javascript-api
https://mermaid-js.github.io/mermaid/landing/
integrations
language-highlight
markdown
mermaidAPI
mermaidCLI
mindmap
more-pages
n00b-advanced
n00b-gettingStarted
n00b-overview
n00b-syntaxReference
newDiagram
pie
plugins
quickstart
requirementDiagram
security
sequenceDiagram
stateDiagram
themes
theming
upgrading
usage
user-journey

These seem to be the possible links. I extracted it out from the markdown files.

flowchart could generate

• https://mermaid-js.github.io/mermaid/#/flowchart
• https://mermaid-js.github.io/mermaid/#/flowchart.md
  with possibility of id links like
• https://mermaid-js.github.io/mermaid/#/flowchart?id=links-between-nodes
• https://mermaid-js.github.io/mermaid/#/flowchart.md?id=links-between-nodes

I think we can ignore the id part as it'll be too much work to map the old and new IDs. The user can find it out in the page.