Support mutlipe backup targets on UI

[a110605]

What this PR does / why we need it

Support mutlipe backup targets feature in longhorn UI

Longhorn UI change Items

• [x] Backup & backup detail page should display correctly since some API schemes changed
• [x] Add new page in Settings -> Backup Target - Display all backup targets in a table - Allow user to create new backup target - delete / edit existing item - bulk delete - filter backup target on page top right
• [x] allow user to choose backup target when creating backup task recurring job.
• [x] allow user to choose backup target when creating backup in volume detail page.
• [x] allow user to choose backup target when creating backup backing image
• [x] Disable create backup in volume detail / backup / system backup pages if no available and writable backup targets

Note. This UI PR need to wait for longhorn-manager and LEP PRs merge first.

• https://github.com/longhorn/longhorn/pull/6630
• https://github.com/longhorn/longhorn-manager/pull/2182

Issue

[UI][FEATURE] Multiple backup stores support

Test Result

Backup detail page should display correct backups (the backup belongs to that backup target)

CRUD operations in Settings -> Backup Target page

https://github.com/longhorn/longhorn-ui/assets/5744158/6aaf2180-c5a2-40f7-b0a0-2759a1c9c4d0

Allow user to choose backup target when creating backup task recurring job.

https://github.com/longhorn/longhorn-ui/assets/5744158/16bb075b-5f72-41b1-bd62-b0e1e4f2da7a

Allow user to choose backup target when creating backup in volume detail page

https://github.com/longhorn/longhorn-ui/assets/5744158/3a037403-df08-4eda-a13f-1790d4fb98cf

Allow user to choose backup target when creating backup backing image

https://github.com/longhorn/longhorn-ui/assets/5744158/50451be8-ed37-4d2b-b5cd-cce19fc53118

Additional documentation or context