Add copy button to code snippets

[karuppiah7890]

Change Request

Currently https://tikv.org website shows code snippets with no copy button, at least in this page - https://tikv.org/docs/5.1/concepts/tikv-in-5-minutes and this one - https://tikv.org/docs/5.1/develop/clients/java/

Describe the problem

• Relevant URL(s): https://tikv.org/docs/5.1/concepts/tikv-in-5-minutes , https://tikv.org/docs/5.1/develop/clients/java/

Suggest an improvement/fix

We can follow a solution similar to many other sites which provide copy button, including TiDB site, for example - https://docs.pingcap.com/tidb/stable/tiup-overview has code snippets / CLI command snippets with copy buttons