feat: add xontrib to support Fire in the xonsh shell

[anki-code]

Workflow:

xonshxpipinstallfire# xontrib will be installed with the main package seamlessly.xontribloadfiretype(@)
# xonsh.built_ins.XonshSessionInterfacefire @ --help# @ - Xonsh Session Interfaceobj= {'var': 'val'}
fireobjvar# val
type(@.env)
# xonsh.environ.Envfire @.envgetUSER-upper# PCtype(aliases)
# xonsh.aliases.Aliasesfirealiasesgetls# ls -Gtype(@.imp)
# xonsh.built_ins.InlineImporterfire @.imp.jsondumps--help# @.imp.json dumps OBJ <flags>fire @.imp.jsondumps'{"a":1}'--indent4# {# "a": 1# }

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