Consider alternative to select input for multiple JSON examples

[jpmckinney]

See comments here: https://github.com/open-contracting/standard/pull/961/files/310b35f2ade751b07a12ad68d50241a2e696bad4#diff-66f1cde311f2d2dbc362185a195768fd

[jpmckinney]

We can use https://sphinx-inline-tabs.readthedocs.io/en/latest/ https://sphinx-design.readthedocs.io/en/rtd-theme/tabs.html

Ref: open-contracting/standard_profile_template#38