QuteErrorPageSetup: support templates that are not backed by a file #46909

Job	Run time
CI Sanity Check	31s
Attach pull request number	3s
Initial JDK 17 Build	10m 57s
Calculate Test Jobs	10s
Maven Tests - JDK 17	7m 44s
JVM Tests - JDK 17	15m 2s
Maven Tests - JDK 17 Windows	11m 44s
JVM Tests - JDK 21	15m 17s
Devtools Tests - JDK ${{ matrix.java.name }}	0s
Gradle Tests - JDK ${{ matrix.java.name }}	0s
JVM Tests - JDK 17 Windows	23m 29s
Kubernetes Tests - JDK ${{ matrix.java.name }}	0s
Quickstarts Compilation - JDK 17	7m 10s
Native Tests - Misc1	7m 3s
Native Tests - Misc2	4m 27s
MicroProfile TCKs Tests	0s
Native Tests - Windows support	7m 19s
Native Tests - Virtual Thread - Main	3m 48s
Upload build stats to collector	0s
Build report	32s
	1h 55m 16s

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