Add methods to sort license JSON and license JSON TOC

[bact]

To get more stable JSON output

• ExceptionJsonTOC.sort() -- same logic as in Sort the JSON TOC files LicenseListPublisher#149
• LicenseJsonTOC.sort() -- same logic as in Sort the JSON TOC files LicenseListPublisher#149
• LicenseJson.sortCrossRef() -- will be used by Sort crossRef members in JSON output LicenseListPublisher#244

Note

For LicenseListPublisher, to sort crossRef in the JSON output, apply spdx/LicenseListPublisher#244 after the change is this PR is released.

[bact]

Should I add sort for LicenseJsonTOC and ExceptionJsonTOC in this PR too? Both are small.

[pmonks]

@bact seems to me that deterministic ordering of all elements may be important.

[goneall]

LGTM - Thanks @bact