[sdk] Expand DSL capabilities of ExpressionArgumentBuilder

[johnhammerlund]

ExpressionArgumentBuilder currently only supports the basic buildBlock(...) method, but not loop expressions or conditional expressions. There are cases where these can simplify logic, reduce constants, etc. For example, a SymbolLayer may have a large matrix of icons:

let iconImageExp = Exp(.match) {
    "make"
    
    "ford"
    Exp(.match) {
        "color"
        
        "red"
        "red-ford-icon"

        "green"
        "green-ford-icon"
    }

    "chevy"
    Exp(.match) { ... }
}

We could instead leverage Swift a bit more:

let iconImageExp = Exp(.match) {
    "make"
    for make in CarMake.allCases {
        make.featureValue
        Exp(.match) {
            "color"
            for color in CarColor.allCases {
                color.featureValue
                make.iconID(color: color)
            }
        }
    }
}

The second example is not currently possible. This PR adds support for loops/arrays as well as conditionals. Some feature examples have been updated to leverage this, but happy to revert that if desired.

Pull request checklist:

• Describe the changes in this PR, especially public API changes.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality. Put tests in correct Test Plan (Unit, Integration, All)
  • If tests were not written, please explain why.
• Add documentation comments for any added or updated public APIs.
• Add any new public, top-level symbols to the DocC custom catatlog (Sources/MapboxMaps/Documentation.docc/API Catalogs)
• Add a changelog entry to to bottom of the relevant section (typically the ## main heading near the top).
• Update the guides (internal access only), README.md, and DEVELOPING.md if their contents are impacted by these changes.
• If this PR is a v10.[version] release branch fix / enhancement, merge it to main first and then port to v10.[version] release branch.

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[CLAassistant]

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[OdNairy]

Looks great! Thank you, @johnhammerlund
I will get back to the PR next week, review and merge it 👍

P.S. (just for me) The internal ticket for this request was MAPSIOS-413

[OdNairy]

Also congrats on your first PR 🎉

[johnhammerlund]

Hello @OdNairy , any updates on this? Thanks!

[OdNairy]

Hey @johnhammerlund
Sorry for a delay. I've merged your PR to the different base branch so I could process it appropriately internally

[OdNairy]

@johnhammerlund Heads up that PR was merged and available in the main branch:

• a81ebe1

Thank you very much for such a nice addition!

[johnhammerlund]

Excellent, appreciate it! Thanks @OdNairy 👍