Add checksum verification to TSM inspect tool

[jwilder]

TSM files contain a checksum per block. The inspect_tsm tool should be updated to be able to verify and report any blocks that fail verification.

Original issue from #4977

[seiflotfy]

I am working on this, these are my steps:

• implement validate on block in tsm1 reader
• expose to inspect_tool

[seiflotfy]

What is the expected behaviour here? https://github.com/influxdata/influxdb/blob/master/tsdb/engine/tsm1/reader.go#L910
Return error?

[jwilder]

@seiflotfy It should not validate there. That TODO and others can be removed. The influx_inspect tool should be able to report the issue.

[toddboom]

Agreed. I think for now, the only goal is to have the tool run the verification. The database itself won't do any checksum enforcement yet.

[seiflotfy]

OK on it!