Support LAMBDA in the Apalache IR

[shonfeder]

The Apalache IR has not yet picked up support for TLA LAMBDA. Instead we perform a de-lambdification to convert any lambdas into let expressions. However, let expressions cannot be applied, as noted in #2517.

This has required workarounds in quint conversion:

• Fix conversion of quint foldr #2500
• Fix conversion of quint select #2515
• Conversion of quint Map.setBy produces invalid Apalache IR #2531

Adding support for LAMBDA in the IR will have at least the following benefits:

• Reduce complexity of quint conversion.
• Improve readability of TLA we generate from parsed specs (e.g., as recorded with --write-intermediate)
• Reduce complexity of our pre-processing, since we won't need to de-lambdafy.

See also #251, #872