Restructure naming format in benchmark results

[darshanasbg]

This is regarding: https://github.com/wso2/performance-is/tree/master/benchmarks

Current filenames are as follows.
single-node-2-core-5.8.0-2019-05-14.md
single-node-4-core-5.8.0-2019-05-09.md
single-node-4-core-5.9.0-2019-10-03.md
2-node-cluster-2-core-5.8.0-2019-05-30.md
2-node-cluster-4-core-5.8.0-2019-05-24.md

We should remove the date as it does not effect for the perf result. As we plan to maintain pre-release results (milestones,alpha,beta,rc results) as well as post release results (wum packs) we need to have exact release version of the pack in the filename.

As an external user will be mostly looking for a performance benchmarks for a particular product version, IMO we can have the first identifier as product version number then go to the deployment details. Like,

• 5.8.0-beta6_single-node_4-core.md
• 5.8.0-rc2_single-node_2-core.md
• 5.8.0_two-nodes_2-core.md
• 5.8.0_two-node_4-core.md
• 5.9.0_single-node_4-core.md

Need to think on the formatting with the docker based deployments as well.

[aaujayasena]

Add heap size, db instance type, jvm, os parameters when naming the results, if results are with different in mentioned parameters.