rimage/cmake: add find_package(OpenSSL ...) #15100

Job	Run time
build-linux (mnfst, imx8 imx8x imx8m)	7m 14s
build-linux (mnfst, mtl)	5m 33s
build-linux (mnfst, lnl)	6m 53s
build-linux (mnfst, tgl tgl-h)	6m 58s
build-windows (imx8 imx8x imx8m)	5m 52s
build-linux (zmain, imx8 imx8x imx8m)	6m 35s
LP64-WIP	6m 7s
build-windows (mtl)	5m 7s
build-linux (zmain, mtl)	6m 22s
build-windows (tgl tgl-h)	5m 22s
build-linux (zmain, lnl)	6m 27s
build-windows (-d, mtl)	5m 55s
manifest-check	51s
build-linux (zmain, tgl tgl-h)	6m 46s
build-linux (-d, mnfst, mtl)	5m 42s
compare-linux-win	56s
	1h 28m 40s

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