Adds new internal package cveclient, a Go client for the MITRE CVE
Services API. Implements functionality to reserve new IDs, lookup
existing IDs, lookup quota, and list IDs for an organization.

Also adds a command line tool 'cve' to call the client functions.

For golang/go#53256

Change-Id: I10fad48adbdac32485ddf05975e2604021607079
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/409995
Reviewed-by: Julie Qiu <julieqiu@google.com>
Reviewed-by: Tatiana Bradley <tatiana@golang.org>
Auto-Submit: Tatiana Bradley <tatiana@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Julie Qiu <julieqiu@google.com>

Adds a new command, cve publish, which can be used to publish CVE
Records to MITRE from YAML reports or JSON files. Also adds a cve record
command to look up existing CVE records by ID. The commands are
currently only supported in the test environment as the MITRE API does
not yet support the commands in production.

To support these commands, this CL also contains logic to convert YAML
report files to the new CVE JSON 5.0 format.

For golang/go#53256

Change-Id: I024bb18a2ece851724ca97f2f6d77f6aafc956b0
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/411514
Reviewed-by: Tatiana Bradley <tatiana@golang.org>
Reviewed-by: Julie Qiu <julieqiu@google.com>

MITRE now supports publishing and looking up CVEs via a prod API
(https://github.com/CVEProject/cve-services), so our "cve" command no
longer errors when a user attempts to publish or view a record in the
prod environment.

This CL also fixes the endpoint for the "cve record" command which was
incorrect.

For golang/go#53256

Change-Id: I1a28f9607de1253a5e9bdeb1249f44de4b8f7e47
Reviewed-on: https://go-review.googlesource.com/c/vulndb/+/446216
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Tatiana Bradley <tatiana@golang.org>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Tatiana Bradley <tatiana@golang.org>