The previous situation was confusing with various contradicting
(staments of) defaults, mixed with old style and new style
configuration.

Simplify by deciding that having backtraces is so
useful that it is the defaut, both old and new style configurations.
(It was already default on in the config template,
which seems 'canonical'.)

Although strictly 'less correct'. When manually converting
metadata, this is not such a useful note, and frequently gives
rise to trouble when the output is copied to somewhere static.

Previously, would show inappropriate precision, like "0.0598134 hours ago"
or "1490532.4129 hours from now" depending on the expiration date.

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.15 to 4.17.19.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.15...4.17.19

)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Remove master-slave metaphor

Follow the suggestions of [draft-knodel-terminology-00](https://tools.ietf.org/id/draft-knodel-terminology-00.html)
and other language frameworks and replace the notion of master/slave
with a more neutral primary/secondary.

* Configurable ProviderName

Co-authored-by: Tim van Dijen <tvdijen@gmail.com>

Closes #1346

Start testing admin-module

Fix ArtifactResolution due to misuse of Issuer

Convert to our wrapper class for assertions

Few small improvements

Check explicitly whether array element is defined

Check whether http://macedir.org/entity-category is set in the EntityAttributes
before using it as argument in in_array(). This prevents a "TypeError:
in_array() expects parameter 2 to be array, null given" error.

This situation happens when we do have EntityAttributes in the metadata but
none of type "http://macedir.org/entity-category". An example is an IdP
supporting https://refeds.org/category/research-and-scholarship, which would
have "http://macedir.org/entity-category-support" but not per se also
"http://macedir.org/entity-category".

We can remove several tags, login:processing and admin:metaconv_selectfile, and
replace several others with their English text.

It's easiest prevented by adding a linebreak after the <code> tag. This is not
ideal but a quick fix.