Peakrdl-ipxact

**Updates:**
* If exporting standard does not support the `isPresent` tag, discard nodes that are marked not present via `ispresent=false`.

**Updates:**
* Fix handling of fields with reset value as a reference

**Bugfixes:**
* Generate unique names for field instance names if collisions exist in IP-XACT input.
* Fix edge cases in derivation of `hw` property w.r.t. volatile qualifier. 21

**Bugfixes:**
* Assign best-guess for `hw` property when importing from IP-XACT. 21
* Add flexibility to xmlns matches when importing

**Bugfixes:**
* Add missing SPIRIT namespace URI variant for importer

**Updates:**
* Remove deprecated `peakrdl.ipxact` namespace package. 9
* Importer: Migrate to more performant ElementTree API. 15
* Rework PeakRDL command-line plugin mechanism.