feat: section ordering lint rule

[adthrasher]

This pull request adds a new rule to wdl-lint.

• Rule Name: SectionOrdering

This rule ensures that tasks and workflows have their sections in the desired order.

Before submitting this PR, please make sure:

• You have added a few sentences describing the PR here.
• You have added yourself or the appropriate individual as the assignee.
• You have added at least one relevant code reviewer to the PR.
• Your code builds clean without any errors or warnings.
• You have added an entry to the relevant CHANGELOG.md (see
  ["keep a changelog"] for more information).
• Your commit messages follow the [conventional commit] style.

Rule specific checks:

• You have added the rule as an entry within RULES.md.
• You have added the rule to the rules() function in wdl-lint/src/lib.rs.
• You have added a test cases in wdl-lint/tests/lints that covers every
  possible diagnostic emitted for the rule within the file where the rule
  is implemented.
• You have run wdl-gauntlet --refresh to ensure that there are no
  unintended changes to the baseline configuration file (Gauntlet.toml).
• You have run wdl-gauntlet --refresh --arena to ensure that all of the
  rules added/removed are now reflected in the baseline configuration file
  (Arena.toml).