cli: Add --no-merge-similar for "result list" and "result show"

We have a problem; the same config, when installed on 2 different suts,
may have a slightly different fingerprint, so there will be 2 separate
entries in the database. For instance, if the rootfs location is
different, the kernel_cmdline_full_hash will be different between the 2
machines. And it's possible the userspace_name may differ if the Ubuntu
point release is different for example.

So let's disregard these small differences by default; we will still
keep the separate entries in the resultstore, but unless told otherwise,
we will merge similar configs and fix up all the references from the
other tables when we read the data in. This means we can easily compare
benchmarks across different suts. If the user knows better, they can opt
out of this merging behavior by specifying --no-merge-similar.

Additionally, let's also merge similar benchmarks so that the container
image can change without considering it a new benchmark by default.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>