[MNG-6230] Separate plugin dependencies and execution declarations

**[Peter Cummuskey](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=tzrlk)** opened **[MNG-6230](https://issues.apache.org/jira/browse/MNG-6230?redirect=false)** and commented

Proposed example:

```

...

bongo
com.bongo.morebongo
allthebongo
1.1.0-BONGO

bongo-run
bongo
generate-sources
bongotime

false

maven-compile

```

Does any of that sound reasonable?

---

**Affects:** Issues to be reviewed for 4.x

**Issue Links:**
- [MNG-3397](https://issues.apache.org/jira/browse/MNG-3397) [RFC] change the POM to use attributes

The issue proposes a Maven 4.x redesign of plugin dependency and execution declarations but names no source files or tests. Start by reviewing MNG-6230 and the linked MNG-3397 RFC, then identify the affected POM model and build-processing entry points. Done would require an agreed design and corresponding implementation scope, which the issue does not define.

Written by the indexing model from the issue text.