fix(core): provide API for plugins to customise hawtconfig programmatically

[tadayosi]

Changes required to support branding customisation by a WAR plugin such as Artemis plugin.

[github-actions]

Test Results

    8 files  ±0      8 suites  ±0   39m 59s ⏱️ -35s
  59 tests ±0    58 ✔️ +1  1 💤 ±0  0 ❌  - 1 
468 runs  ±0  460 ✔️ +1  8 💤 ±0  0 ❌  - 1 

Results for commit 9152608. ± Comparison against base commit b072055.

[hawtio-ci]

Test results

Run attempt: 956
Detailed summary

NAME	TESTS	PASSED ✅	SKIPPED 💤	FAILED ❌	ERRORS 🚫	TIME 🕖
results-quarkus-node(18)-java(11)-firefox	59	58	1	0	0	293.039
results-quarkus-node(18)-java(17)-firefox	59	58	1	0	0	297.905
results-quarkus-node(20)-java(11)-firefox	59	58	1	0	0	322.103
results-quarkus-node(20)-java(17)-firefox	59	58	1	0	0	321.372
results-springboot-node(18)-java(11)-firefox	58	57	1	0	0	293.667
results-springboot-node(18)-java(17)-firefox	58	57	1	0	0	283.545
results-springboot-node(20)-java(11)-firefox	58	57	1	0	0	301.035
results-springboot-node(20)-java(17)-firefox	58	57	1	0	0	286.67