Add support for Mise to install Ant and Java - #462

@jeff5 , please add Mise support to the Jython repo.

Mise makes it easy to build Jython on Windows, Linux, and macOS.

mise install ensures that both ant and java (8) is installed.

Building Jytthon is then a simple matter of just running: ant

I haven't found it that inconvenient to select a JVM and Python version without mise. Ok, I have PowerShell scripts equivalent to what mise does, and this is a bit clunky, but use is infrequent.

We try to avoid checking in configuration for tools that are there only to support the preferences of individual developers. People may have other ways they like already of preparing their shell, or prefer a different JVM. Up to a point, this diversity is useful. Checking them in means they keep changing.

I suggest:

• Recommend mise in README.md (or maybe in ProcessDocs) as a way of setting your environment and suggest a mise.toml as a code block.
• Add a line to .gitignore so mise.toml is not checked in, so if there are ever 2 mise users in Jython, we don't fight over the contents.

This topic is worth discussing further. Mise is becoming a very popular to install build tool dependencies and also run tasks. In order to build and run Jython one currently has to install Java 8 and Ant. Very few developers have these tools installed on the machines these days.

Mise is very easy to install (easier than installing Ant and Java 8 individually) and thereafter one only has to run mise install to ensure Ant and Java 8 is installed. Mise will even fetch the latest available versions of these two tools. Mise also correctly configures the PATH and other environment varialbles. I have switched to Mise from SDKMAN, because SDKMAN does not support Windows.

The mise.toml file below also contains additional tasks for testing and building Jython that I find useful.

[tools]
ant = "latest"
java = "temurin-8"

[tasks.regrtest]
dir = "dist/bin"
run = "jython -m test.regrtest"

[tasks.regrtest-all]
dir = "dist/bin"
run = "jython -m test.regrtest -u network"

[tasks.jython-version]
dir = "dist/bin"
run = "jython -V"

[tasks.build]
run = [
    "ant clean", 
    "ant",
    { task = "jython-version" }
]

Having support for mise.toml in the Jython project, will actually make it easier for newcomers to be able to build and run Jython.

• mise build

Installing Mise in Powershell on Windows is easy:

• irm https://mise.run/powershell | iex

Similar setup commands are available for MacOS and Linux.

This is what mise install does on Windows, the first time it is run in the Jython folder (in this example, mise is auto-updating itself because an older version was installed on Windows):

The following screenshot shows how Mise is integrated into IntelliJ IDEA via a plugin: