RFR: 7033: Allow overriding the id (name) of the event type [v2]

[Gunnar Morling]

> @thegreystone et al., this PR proposes two changes to the names of generated event types and their fields:
> 
> * An explicit event type name is derived from the name given in the configuration, instead of using the class name; this is nicer to work with e.g. when enabling/disabling event types for recordings
> * the "field" prefix is removed from event type field names; when examining e.g. `RecordedEvent` instances, names are nicer to look at that way IMO
> 
> Could you log an issue for this change if you agree it's desirable? Thanks! I ran into these issues while using JMC Agent for [tracking SQL statements](https://twitter.com/gunnarmorling/status/1333152245463064579); note the odd "fieldSQLQuery" name marked on the left; the event type name is already adjusted in this screenshot as per this PR here.

Gunnar Morling has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  7033: Nicer names for event types and fields

-------------

Changes: https://git.openjdk.java.net/jmc/pull/170/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jmc&pr=170&range=01
  Stats: 25 lines in 2 files changed: 13 ins; 5 del; 7 mod
  Patch: https://git.openjdk.java.net/jmc/pull/170.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/170/head:pull/170

PR: https://git.openjdk.java.net/jmc/pull/170