[Taxonomy] Add API for plugin-introduced bootstraps

Issue nasa/mct#207 describes the need
for allowing third-party plug-ins to
introduce their own bootstrap components.
This adds appropriate method signatures
to plug-in API to facilitate this. This
does not include any implementation for
the usage of this API.
[Taxonomy] Use plugin bootstrap API

When bundles are refreshed, aggregate all
bootstrap components exposed by plugins,
filter out any which have been previously
written to the database, and persist.
[Taxonomy] Add Bootstrap capability definition

Adds a Bootstrap capability which
bootstrap components may support in
order to provide additional information,
such as ordering, related to such
components.
[Taxonomy] Use Bootstrap capability

Use the Bootstrap capability to determine
if a component should appear as a global
or creator-specific bootstrap component,
when tagging bootstrap components exposed
by plugins.
[Taxonomy] Use capability to find My Sandbox
[Taxonomy] Sort bootstrap components
[Taxonomy] Updated version requirements

Updated package versions required in
bundles to reflect increment in
package version due to introduction
of Bootstrap capability.
[Taxonomy] Support Bootstrap capability in Sandbox

Add Bootstrap capability to My Sandbox.
This identifies the sandbox as the
default destination for new components
to the platform, and provides indexing
information to ensure that My Sandbox
always appears at the last position
in the User Environment.
[Taxonomy] Support Bootstrap capability in taxonomy comp

Add Bootstrap capability to
TelemetryDataTaxonomyComponent. These
are not always bootstraps, but when they
are bootstraps, they should be located
shortly before My Sandbox.
[Taxonomy] Change comment to satisfy checkstyle
[Taxonomy] Test bootstrap components
[Taxonomy] Test bootstrap comparator
[Taxonomy] Test changes to registry

Verify that the external component registry
does probe plugins for bootstrap components,
and does deliver these components to
persistence.
Merge pull request #208 from VWoeltjen/mct207

[Taxonomy] Allow plug-ins to introduce bootstrap components