make the RPATH section check with readelf -d in sanity check optional

[bedroge]

See easybuilders/easybuild-easyblocks#2913 and easybuilders/easybuild-easyconfigs#17516, this makes it easier for easyblocks like GoPackage to skip this check. The check is still enabled by default.

Additionally, it would be nice to have an easyconfig parameter to disable the check for individual packages (e.g. git-lfs), but that can be done in a follow-up PR.

[casparvl]

I haven't looked in detail, but I think this PR might need a test that intentionally installs something without RPATH, and checks that it passes if this RPATH skipping option is used. (I'm assuming there already is a test that checks if the RPATH sanity check fails if the RPATH is not set, RPATH support is used, and the RPATH sanity check fails. In case that's not there, it should also be added)

[boegel]

lgtm

[boegel]

@casparvl You make a good point about adding a test, but all this is doing is adding support for using check_readelf_rpath=False in an easyblock when calling out to the parent sanity_check_rpath, it doesn't actually change anything at all.

Implementing a good test for this would be quite involved, and since this is blocking easybuilders/easybuild-easyblocks#2913, I'll go ahead and merge this...