feat/Adding support for which-language --all

[blast-hardcheese]

Why

Determining which languages are currently in play is a useful operation. For example:

~/workspace$ ./cmd/upm/upm which-language --all | \
                xargs -I% ./cmd/upm/upm list --all --format json --lang %

[{"name":"click","version":"8.1.7"},{"name":"markupsafe","version":"3.0.2"},{"name":"workspace","version":"0.1.0"},{"name":"blinker","version":"1.8.2"},{"name":"colorama","version":"0.4.6"},{"name":"flask","version":"3.0.3"},{"name":"itsdangerous","version":"2.2.0"},{"name":"jinja2","version":"3.1.4"},{"name":"werkzeug","version":"3.0.6"}]
[{"name":"follow-redirects","version":"1.15.9"},{"name":"@types/node","version":"20.12.14"},{"name":"@types/bun","version":"1.1.12"},{"name":"combined-stream","version":"1.0.8"},{"name":"delayed-stream","version":"1.0.0"},{"name":"form-data","version":"4.0.1"},{"name":"mime-types","version":"2.1.35"},{"name":"proxy-from-env","version":"1.1.0"},{"name":"bun-types","version":"1.1.32"},{"name":"asynckit","version":"0.4.0"},{"name":"axios","version":"1.7.7"},{"name":"mime-db","version":"1.52.0"},{"name":"typescript","version":"5.6.3"},{"name":"undici-types","version":"5.26.5"},{"name":"@types/ws","version":"8.5.12"}]

What changed

• Added --all to which-language
• Added IsActive to the api.LanguageBackend interface and Python/Node backends for now

Test plan

The above command worked