Adopt very_good_analysis and add PR dart checks

[jwr1]

• I switched out flutter_lints for very_good_analysis, which is much more opinionated and makes use of more analysis rules.
• I added a GitHub action to check Dart formatting and analysis on PRs, to ensure Dart code remains consistent. This should be especially helpful for big PRs like Navigation update #358 where a lot of files are affected and creates huge formatting diffs.

I will definitely wait till #358 and #359 are merged before addressing the analysis issues introduced by very_good_analysis. I'm sure the merge conflicts would be a nightmare :)

[jwr1]

Wow, it looks like this one's going to be a dozzy! Before running dart fix --apply, there are 2161 issues found. After running the command, there are still 803 issues found that would need to be manually fixed!

Analysis before fix (2161 issues)

441 cast_nullable_to_non_nullable
149 prefer_final_locals
138 lines_longer_than_80_chars
118 avoid_dynamic_calls
109 directives_ordering
105 sort_constructors_first
 96 prefer_const_constructors
 93 discarded_futures
 81 omit_local_variable_types
 76 unawaited_futures
 71 always_put_required_named_parameters_first
 51 prefer_final_in_for_each
 49 unnecessary_null_checks
 42 unused_local_variable
 40 argument_type_not_assignable
 36 avoid_catches_without_on_clauses
 32 avoid_positional_boolean_parameters
 28 avoid_redundant_argument_values
 25 prefer_const_declarations
 25 always_use_package_imports
 23 use_if_null_to_convert_nulls_to_bools
 23 inference_failure_on_function_invocation
 21 unnecessary_this
 21 specify_nonobvious_property_types
 18 unnecessary_parenthesis
 18 unnecessary_await_in_return
 16 avoid_void_async
 13 unnecessary_lambdas
 13 cascade_invocations
 12 prefer_int_literals
 11 unnecessary_breaks
 11 prefer_null_aware_method_calls
 11 for_in_of_invalid_type
 11 flutter_style_todos
 11 deprecated_member_use
  9 inference_failure_on_function_return_type
  9 always_declare_return_types
  8 parameter_assignments
  8 only_throw_errors
  7 invalid_assignment
  7 inference_failure_on_instance_creation
  6 sort_unnamed_constructors_first
  6 avoid_bool_literals_in_conditional_expressions
  5 not_map_spread
  5 non_bool_condition
  4 inference_failure_on_untyped_parameter
  4 eol_at_end_of_file
  3 use_named_constants
  3 use_build_context_synchronously
  3 return_of_invalid_type_from_closure
  3 prefer_foreach
  3 inference_failure_on_collection_literal
  2 use_late_for_private_fields_and_variables
  2 unnecessary_import
  2 strict_raw_type
  2 sort_pub_dependencies
  2 prefer_const_literals_to_create_immutables
  2 not_iterable_spread
  2 noop_primitive_operations
  2 combinators_ordering
  2 avoid_equals_and_hash_code_on_mutable_classes
  1 use_null_aware_elements
  1 unused_element_parameter
  1 unnecessary_raw_strings
  1 strict_top_level_inference
  1 recursive_getters
  1 prefer_if_elements_to_conditional_expressions
  1 prefer_final_fields
  1 join_return_with_assignment
  1 curly_braces_in_flow_control_structures
  1 collection_methods_unrelated_type
  1 avoid_unused_constructor_parameters
  1 avoid_slow_async_io

Analysis after fix (803 issues)

132 avoid_dynamic_calls
111 discarded_futures
 85 lines_longer_than_80_chars
 82 unawaited_futures
 44 argument_type_not_assignable
 42 unused_local_variable
 36 avoid_catches_without_on_clauses
 32 avoid_positional_boolean_parameters
 24 inference_failure_on_function_invocation
 23 unnecessary_null_checks
 15 specify_nonobvious_property_types
 13 cascade_invocations
 11 prefer_null_aware_method_calls
 11 for_in_of_invalid_type
 11 flutter_style_todos
 11 deprecated_member_use
  9 inference_failure_on_function_return_type
  9 final_and_var
  8 parameter_assignments
  8 only_throw_errors
  8 inference_failure_on_instance_creation
  7 invalid_assignment
  5 not_map_spread
  5 non_bool_condition
  4 use_named_constants
  4 not_a_type
  4 inference_failure_on_untyped_parameter
  4 extra_positional_arguments_could_be_named
  3 use_build_context_synchronously
  3 return_of_invalid_type_from_closure
  3 prefer_foreach
  3 inference_failure_on_collection_literal
  3 expected_token
  2 use_late_for_private_fields_and_variables
  2 strict_raw_type
  2 sort_pub_dependencies
  2 not_iterable_spread
  2 extra_positional_arguments
  2 duplicate_definition
  2 directives_ordering
  2 avoid_equals_and_hash_code_on_mutable_classes
  1 strict_top_level_inference
  1 recursive_getters
  1 non_type_as_type_argument
  1 non_constant_identifier_names
  1 non_bool_negation_expression
  1 missing_method_parameters
  1 missing_function_body
  1 join_return_with_assignment
  1 implicit_this_reference_in_initializer
  1 final_not_initialized_constructor
  1 collection_methods_unrelated_type
  1 avoid_types_as_parameter_names
  1 avoid_slow_async_io
  1 always_declare_return_types

[jwr1]

I ended up adding quite a few rules to the ignore list. A good bit of them were related to our use of dynamic in some places. We can save working on those for another day, as it would be a lot of effort to resolve every single one of them. Still, this is a huge improvement over what we are currently working with.

[jwr1]

Looks like this issue is causing dart fix to error out: dart-lang/sdk#62068