Those are *always* /proc/self/exe init, and it does not make sense
to ever change these. More to say, if InitArgs option func (removed
by this commit) is used to change these parameters, it will break
things, since "init" is hardcoded elsewhere.

Remove this.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

We only have one implementation of config validator, which is always
used. It makes no sense to have Validator interface.

Having validate.Validator field in Factory does not make sense for all
the same reasons.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

These were introduced in commit d8b6694 back in 2017, with a TODO
of "make binary names configurable". Apparently, everyone is happy with
the hardcoded names. In fact, they *are* configurable (by prepending the
PATH with a directory containing own version of newuidmap/newgidmap).

Now, these binaries are only needed in a few specific cases (when
rootless is set etc.), so let's look them up only when needed.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

Since we are looking up the path to newuidmap/newgidmap in one context,
and executing those in another (libct/nsenter), it might make sense to
use a stricter rules for looking up path to those binaries.

Practically it means that if someone wants to use custom newuidmap and
newgidmap binaries from $PATH, it would be impossible to use these from
the current directory by means of PATH=.:$PATH; instead one would have
to do something like PATH=$(pwd):$PATH.

See https://go.dev/blog/path-security for background.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

TestGetContainerStats test a function that is smaller than the test
itself, and only calls a couple of other functions (which are
represented by mocks). It does not make sense to have it.

mockIntelRdtManager is only needed for TestGetContainerStats
and TestGetContainerState, which basically tests that Path
is called. Also, it does not make much sense to have it.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

Remove intelrtd.Manager interface, since we only have a single
implementation, and do not expect another one.

Rename intelRdtManager to Manager, and modify its users accordingly.

Remove NewIntelRdtManager from factory.

Remove IntelRdtfs. Instead, make intelrdt.NewManager return nil if the
feature is not available.

Remove TestFactoryNewIntelRdt as it is now identical to TestFactoryNew.

Add internal function newManager to be used for tests (to make sure
some testing is done even when the feature is not available in
kernel/hardware).

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>