Add templates for version replacements

[Dr-Electron]

Is your feature request related to a problem? Please describe.

To minimise the problems with merging different version, we should provide variables that replace certain templates so that merging docs won't be a problem (see examples at the end of this issue)

Describe the solution you'd like

We maybe could use rehype-lodash-template or a similar tool to have a list of templates/variables that in the docs will be replaced with the corresponding strings.

For urls this may also be of help: rehype-url-inspector (It could even help with broken links)

Describe alternatives you've considered

Doing it manually

Additional context

In the docs you could for example use ${ENVIRONMENT_URL}/hornet/welcome which in a Shimmer environment would point to https://wiki.iota.org/shimmer/hornet/iota.org (or even better use the config parameters) and in an IOTA environment to https://wiki.iota.org/hornet/iota.org

Or another markdown example:

In ${NETWORK} you always need a storage deposit

where ${NETWORK} will be replaced with either IOTA or Shimmer

[Dr-Electron]

Blocked because I can't get it to work as this is an ESM module and Docusaurus doesn't like me 😢

Normally this should work like described in the note here: https://docusaurus.io/docs/markdown-features/plugins#installing-plugins

If this doesn't work with this plugin we would need to wait for official ESM support. (Which maybe already comes with version 3.0 which should be the next release 🤔 )