add new Array and Map types

[Geal]

this tries to enforce that all array elements are of the same type, but this is not very strict at the moment, it does not look at lower levels of composite types.

breaking changes:

• in the Datalog language, sets will now be delimited by '{' and '}' instead of '[' and ]'. Arrays are now delimited by '[' and ']'
• parameter names must now start with a letter

Todo:

• [x] array serialization
• [x] array parsing
• [x] existing operations for array: length, equal, not equal, contains, prefix, suffix
• [x] map serialization
• [x] map parsing
• [x] existing operations for map: length, equal, not equal, contains, prefix, suffix
• [x] new operations for array: get (with integer index), closures
• [x] new operations for map: get (with integer or string index), closures

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #219 will not alter performance

_{Comparing map-array (ab861d1) with v5 (22bd667)}

Summary

✅ 12 untouched benchmarks

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 72.92419% with 75 lines in your changes missing coverage. Please review.

Project coverage is 68.83%. Comparing base (525c278) to head (0399b2f).

:exclamation: Current head 0399b2f differs from pull request most recent head d5003f3

Please upload reports for the commit d5003f3 to get more accurate results.

Files	Patch %	Lines
biscuit-parser/src/builder.rs	41.46%	24 Missing :warning:
biscuit-auth/src/token/builder.rs	78.88%	19 Missing :warning:
biscuit-auth/src/datalog/expression.rs	81.33%	14 Missing :warning:
biscuit-parser/src/parser.rs	55.00%	9 Missing :warning:
biscuit-auth/src/datalog/mod.rs	0.00%	4 Missing :warning:
biscuit-auth/src/format/convert.rs	78.94%	4 Missing :warning:
biscuit-auth/src/datalog/symbol.rs	93.33%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v5 #219 +/- ## ========================================== + Coverage 68.57% 68.83% +0.25% ========================================== Files 25 25 Lines 5681 5932 +251 ========================================== + Hits 3896 4083 +187 - Misses 1785 1849 +64 ```

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