feat: implement a WDL lexer using logos.

[peterhuene]

This commit introduces an experimental module as a placeholder for a new parser implementation, feature-gated by the experimental feature.

To start, a lexer implementation based on logos has been added.

The lexer may have several different token types depending on context, mainly to support interpolation in string literals and commands.

The implementation should be enough to lex a 1.x WDL document.

The parser implementation that will make use of the lexer is forthcoming.

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[a-frantz]

I think you know this, but for the time being we're going to ignore the Gauntlet CI(Though we should make an attempt at reworking it sooner rather than latter)