Mkdocs-markmap

* Update markmap libraries to `0.15.x`
* Support custom static assets
* Allow removing the default assets

* Updates markmap-lib to `0.14.1`
* Updates markmap-view to `0.14.0`
* Updated python dependency to `>=3.7`
* Updates repository name to `markamp/mkdocs-markmap`

* Fixes [API issue with Markdown 3.4+](https://github.com/neatc0der/mkdocs-markmap/issues/39)

* Fixes [static javascript files bug](https://github.com/neatc0der/mkdocs-markmap/issues/35)

* Adds [support for mkdocs-encryptcontent-plugin](https://github.com/neatc0der/mkdocs-markmap/issues/26)
* Adds troubleshooting for [nav tree lists markmap files](https://github.com/neatc0der/mkdocs-markmap/issues/33)
* Fixes distribute workflow

* Fixes [superfences 9.0 bug](https://github.com/neatc0der/mkdocs-markmap/issues/27)