feat: Add reproducible build profile

[MoeMahhouk]

Context: While trying to build reproducible confidential VMs with Reth, I noticed that the Reth binary does not build reproducible by design. Consequently, the VMs were not able to be built reproducible because of that.

In this PR, I was mainly trying to figure a way to compile the binary reproducibly by eliminating factors that might have impact on that. Those factors could be, timestamps, file path prefixes, metadata, etc... By adding those changes here, I was able to reproducibly build Reth binary twice with the same hash. It could also be inspected by diffoscope.

Steps to reproduce:

• run make build-reproducible
• copy out the binary cp target/reproducible/reth reth-copy-1
• now clean and remove cargo cache to rebuild from scratch make clean && cargo cache -a
• run make build-reproducible again and cope it out cp target/reproducible/reth reth-copy-2
• compare the two binaries: for example by comparing the output of sha256sum reth-copy-1 and sha256sum reth-copy-2 or by running diffoscope on them

PS: I have tested this on the v1.0.5 and not the main branch

Edit: I've added a Dockerfile that builds reth reproducibly on two different machines too. you can run it like this: docker --no-cache build --output=. . It will build the binary and copy it out to the same directory