Add parameter position handling and UI updates for server configuration

[psdzzm]

Add Parameter Position Control

What's Changed

Added ability to control where custom parameters are inserted in nginx configuration blocks, including support for templates and upstream configurations.

Features

• New position field in Param model (0 = append to end, 1 = prepend to beginning)
• UI dropdown to select parameter position in server, location, and upstream configurations
• Template support: "Add Template" and "Add Template as Parameter" now include position control

Files Modified

Backend

• src/main/java/com/cym/model/Param.java - Added position field
• src/main/java/com/cym/service/ConfService.java - Position-aware insertion for location and upstream blocks

Server Page

• src/main/resources/WEB-INF/view/adminPage/server/index.html
• src/main/resources/static/js/adminPage/server/index.js

Upstream Page

• src/main/resources/WEB-INF/view/adminPage/upstream/index.html
• src/main/resources/static/js/adminPage/upstream/index.js

Shared

• src/main/resources/static/js/adminPage/select_template.js - Conditional position column for templates
• src/main/resources/messages*.properties - i18n strings

Backward Compatibility

✅ Existing parameters default to append behavior (position = 0 or null)

[cym1102]

改的有点多, 我有空先看看再说