Centralised dependency list

[guidoiaquinti]

Overview of the Issue

In the codebase there are several places where we manage external dependencies. Unfortunately it's hard to keep them in sync and de-sync can often create issues.

Example:

• https://github.com/vitessio/vitess/blob/master/docker/bootstrap/Dockerfile.common#L3-L38
• https://github.com/vitessio/vitess/blob/master/vagrant-scripts/bootstrap_vm.sh#L17-L35
• https://github.com/vitessio/vitess/blob/master/doc/GettingStarted.md

I'm opening this issue to keep track of the problem and with the hope of discussing a proposal for a single source of truth for all the dependencies needed to build and run Vitess.

[morgo]

The dependency list should be shrinking a lot (use of go modules, converting Python tests to go etc.), which will make it easier to manage.

I will look at updating the build guide in a couple of months time as this work completes. We can then take another look at this issue.

[morgo]

I have been updating the build guides as we trim dependencies. See vitessio/website#372 for a next-generation, where they are quite light.

I also added a dependency_check shell script to the Makefile in #5527

I am going to close this issue now, but please feel free to re-open if you feel this is not sufficiently addressed.