feat: use lend/filter for saved searches, augment url where needed

[mcstover]

This PR updates the saved search page /lend/saved-search to link to /lend/filter instead of legacy lend.

• updates the url path
• removes unnecessary loanLimit param when unset (ie, set to -1)
• removed duplicated separators after query param changes

[mcstover]

Need to do a bit more validation and testing, potentially accomodating other filter formatting

[mcstover]

@dyersituations if any other query params come to mind that need a query param map to be compatible with lend/filter please let me know and we can fold it in here before merging.

[dyersituations]

@dyersituations if any other query params come to mind that need a query param map to be compatible with lend/filter please let me know and we can fold it in here before merging.

The only one at the moment I think is the distribution model ticket, but it's not related 100% to saved search.