Closes #14917: Replace slim-select with tom-select

[jeremystretch]

Fixes: #14917

• Drop slim-select as a dependency & introduce tom-select
• Port custom functionality from legacy APISelect to TomSelect

[jeremystretch]

1. type secondary part of an existing group of ip addresses (for example I have 172.16.0.2, 172.16.0.3..) type '.16' for the filtered list the old select showed all the ip's containing the .16. For the new tom-select it shows 'No Results Found'.

Here's what's happening in the current (v3.7) UI:

1. User opens the dropdown
2. APISelect loads and sends its initial REST API request for /api/ipam/ip-addresses/, populating its first 50 entries
3. User types a value, e.g. .16
4. A second REST API request is issued, this time for /api/ipam/ip-addresses/?q=.16
5. An empty response is received (because partial match on IPs in this manner is not currently supported)
6. APISelect falls back to returning any of the previously retrieved IP addresses matching the query

It's simply coincidence if any matching IP addresses are displayed. We can confirm this by attempting to match on an IP address that is not returned as part of the initial set of values. The only difference in behavior is that the TomSelect implementation does not fall back to matching against cached values.

This issue can only be resolved by implementing support for partial matching on the address field for IP addresses; we'll need to raise a separate bug/FR for that if it seems reasonable. (It's worth noting that matching an IP address by its beginning value, e.g. 192.168.16 does work as expected.)

[jeremystretch]

2. What is worse is if you click off of the dropdown while it is displaying this (click to another dropdown or off to the side) it will now show '----' and if you expand it it will still show 'No Results Found', you have to press the delete key to start getting results again.

The issue here seems to be that the query is not cleared when the field loses focus, nor is it re-displayed when the field regains focus.

This appears to be a bug in tom-select itself: You can observe the same behavior in the first example here.

Edit: I've opened a bug report upstream to see if this something that can/should be tackled in tom-select itself.