* config: add 'pageLoadTimeout' and 'pageExtraDelay' options to backend config
- add 'default_page_load_timeout_seconds' to values.yaml, defaulting to 120, for pageLoadTimeout
- add 'defaultPageLoadTimeSeconds ' to /api/settings, update tests for /api/settings
addresses issue in #636
* backend: max pages per crawl limit, part of fix for #716:
- set 'max_pages_crawl_limit' in values.yaml, default to 100,000
- if set/non-0, automatically set limit if none provided
- if set/non-0, return 400 if adding config with limit exceeding max limit
- return limit as 'maxPagesPerCrawl' in /api/settings
- api: /all/crawls - add runningOnly=0 to show all crawls, default to 1/true (for more reliable testing)
tests: add test for 'max_pages_per_crawl' setting
- ensure 'limit' can not be set higher than max_pages_per_crawl
- ensure pages crawled is at the limit
- set test limit to max 2 pages
- add settings test
- check for pages.jsonl and extraPages.jsonl when crawling 2 pages
