lsp-erlang: add config customization options #5587

Job	Run time
test (ubuntu-latest, 27.2, false)	2m 18s
test (ubuntu-latest, 28.2, false)	2m 36s
test (ubuntu-latest, 29.4, false)	1m 53s
test (macos-latest, 28.2, false)	4m 42s
test (macos-latest, 29.4, false)	5m 35s
test (windows-latest, 27.2, false)	4m 12s
test (windows-latest, 28.2, false)	9m 11s
test (windows-latest, 29.4, false)	3m 22s
test (ubuntu-latest, snapshot, true)	1m 14s
test (macos-latest, snapshot, true)	1m 57s
test (windows-latest, snapshot, true)	4m 49s
	41m 49s

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