[doc] dev - cleanup asdf remnants and add a note about mise-en-place (#5264)

Notes on the developer environment with MISE have been added to the Quickstart
Guide.  We migrated `.tool-versions` to replace it with `mise` [1], so we can
now remove `asdf` related documentation.

[1] https://github.com/searxng/searxng/pull/5253

Co-authored-by: Markus Heiser <markus.heiser@darmarit.de>

docs/dev/index.rst

@@ -7,7 +7,6 @@ Developer documentation
 
    quickstart
    commits
-   rtm_asdf
    contribution_guide
    extended_types
    engines/index

docs/dev/quickstart.rst

@@ -23,6 +23,24 @@ Don't hesitate, just clone SearXNG's sources and start hacking right now ..
 
     git clone https://github.com/searxng/searxng.git searxng
 
+For the developer environment, `mise en place`_ is recommended:
+
+.. code:: sh
+
+   $ curl https://mise.run | sh
+
+The tools required for a developer environment are provided via `mise.toml`_,
+trust the project:
+
+.. code:: sh
+
+   $ mise trust
+
+.. _mise.toml:
+    https://github.com/searxng/searxng/blob/master/mise.toml
+.. _mise en place:
+    https://mise.jdx.dev/getting-started.html
+
 Here is how a minimal workflow looks like:
 
 1. *start* hacking

docs/dev/rtm_asdf.rst

@@ -1,121 +0,0 @@
-==================
-Runtime Management
-==================
-
-The runtimes are managed with asdf and are activated in this project via the
-`.tool-versions <.tool-versions>`_. If you have not yet installed asdf_, then
-chapter :ref:`introduce asdf` may be of help to you.
-
-.. contents::
-   :depth: 2
-   :local:
-   :backlinks: entry
-
-
-Get started
-===========
-
-If you have asdf installed you can install the runtimes of this project by:
-
-.. code:: bash
-
-   $ cd /path/to/searxng
-   $ asdf install          # will install runtimes listed in .tool-versions
-   ...
-
-Manage Versions
-===============
-
-If you want to perform a ``test`` with special runtime versions of nodejs,
-python or shellcheck, you can patch the ``.tool-versions``:
-
-.. code:: diff
-
-   --- a/.tool-versions
-   +++ b/.tool-versions
-   @@ -1,2 +1,2 @@
-   -python 3.12.0
-   -shellcheck 0.9.0
-   +python 3.11.6
-   +shellcheck 0.8.0
-
-To install use ``asdf install`` again.  If the runtime tools have changed, any
-existing (nodejs and python) environments should be cleaned up with a ``make
-clean``.
-
-.. code:: bash
-
-   $ asdf install
-   ...
-   $ make clean test
-
-
-.. _introduce asdf:
-
-Introduce asdf
-==============
-
-To `download asdf`_ and `install asdf`_:
-
-.. code:: bash
-
-   $ git clone https://github.com/asdf-vm/asdf.git ~/.asdf --branch <version>
-   $ echo '. "$HOME/.asdf/asdf.sh"' >> ~/.bashrc
-   $ echo '. "$HOME/.asdf/completions/asdf.bash"' >> ~/.bashrc
-
-Start a new shell and try to `install plugins`_:
-
-.. code:: bash
-
-   $ asdf plugin-list-all | grep -E '(golang|python|nodejs|shellcheck).git'
-   golang                        https://github.com/asdf-community/asdf-golang.git
-   nodejs                        https://github.com/asdf-vm/asdf-nodejs.git
-   python                        https://github.com/danhper/asdf-python.git
-   shellcheck                    https://github.com/luizm/asdf-shellcheck.git
-
-   $ asdf plugin add golang https://github.com/asdf-community/asdf-golang.git
-   $ asdf plugin add nodejs https://github.com/asdf-vm/asdf-nodejs.git
-   $ asdf plugin add python https://github.com/danhper/asdf-python.git
-   $ asdf plugin add shellcheck https://github.com/luizm/asdf-shellcheck.git
-
-Each plugin has dependencies, to compile runtimes visit the URLs from above and
-look out for the dependencies you need to install on your OS, on Debian for the
-runtimes listed above you will need:
-
-.. code:: bash
-
-  $ sudo apt update
-  $ sudo apt install \
-         dirmngr gpg curl gawk coreutils build-essential libssl-dev zlib1g-dev \
-         libbz2-dev libreadline-dev libsqlite3-dev \
-         libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev
-
-With dependencies installed you can install/compile runtimes:
-
-.. code:: bash
-
-  $ asdf install golang latest
-  $ asdf install nodejs latest
-  $ asdf install python latest
-  $ asdf install shellcheck latest
-
-Python will be compiled and will take a while.
-
-In the repository the version is defined in `.tool-versions`_. Outside the
-repository, its recommended that the runtime should use the versions of the OS
-(`Fallback to System Version`_) / if not already done register the system
-versions global:
-
-.. code:: bash
-
-   $ cd /
-   $ asdf global golang system
-   $ asdf global nodejs system
-   $ asdf global python system
-   $ asdf global shellcheck system
-
-.. _asdf: https://asdf-vm.com/
-.. _download asdf: https://asdf-vm.com/guide/getting-started.html#_2-download-asdf
-.. _install asdf: https://asdf-vm.com/guide/getting-started.html#_3-install-asdf
-.. _install plugins: https://asdf-vm.com/guide/getting-started.html#install-the-plugin
-.. _Fallback to System Version: https://asdf-vm.com/manage/versions.html#fallback-to-system-version