Order subsidiary legislation by frbr_uri number

[actlikewill]

• This adds the frbr uri number as a secondary sort parameter for subleg
• The ordering needs to be reversed if the order date sorting is reversed

closes https://github.com/laws-africa/kenyalaw-pj/issues/115

[github-actions]

Test Results

50 tests  +50   50 ✅ +50   12s ⏱️ +12s
13 suites +13    0 💤 ± 0 
13 files   +13    0 ❌ ± 0 

Results for commit c94beb6. ± Comparison against base commit c3a7f40.

♻️ This comment has been updated with latest results.

[actlikewill]

@longhotsummer this is still less than perfect, because we sort primarily by date. First some amendments from earlier years can show up in the current year. Second, some of them are not releaseed chronologically eg. in the screenshot, legal notices 63 and 64 have a date earlier than 55, and the rest following which puts them out of order

[longhotsummer]

I think this is a reasonable start, particularly for recent legislation.