are flattened during loading so that they can be retrieved as useful
types without additional parsing during retrieval.

This change effectively preserves existing behaviour for handling
Strings, Booleans and Integers in flattened configuration while
extending the behaviour to Lists and Maps.

Semantics for interpreting Strings are taken from AgentConfigImpl in the
case of currently supported types, and structured configurations
(AttributesConfig and LabelsConfig) for new types.

general parsing of Strings to Maps does not have labels specific
validation applied.

Applying tag feature to Logback.

General tidy up.

Update LabelsConfigImplTest with potential parse failure scenario.

Break up large method in Logback and Log4J2 instrumentation, as was done
in the Log4J1 PR that added MDC.

Renaming of a couple of constants to reflect what they represent rather
than their value, to avoid longer term confusion if, for example, we
choose to allow multiple delimiters.

…d-logs

Fix conflicts by adding the instrumentation attribute to the event map
of agents that had been updated on feature branch

Add tags, and apply tidy up that was introduced in a previous PR and has
now been applied to all logging agents for consistency.