Rename the remaining env vars that starts with `VITE_`

[liangmiQwQ]

Problem

#1074 and #1166 already rename environment variables which begin with VITE_PLUS_ to VP_. However, there are still some env variables that start VITE_, influencing users' daily using.

List

Original Name	New Name	Description
VITE_GIT_HOOKS	VP_GIT_HOOKS	Vite+ only env vars, for git hooks behavior
VITE_LOG	VP_LOG	Vite+ only, define log level
VITE_GLOBAL_CLI_JS_SCRIPTS_DIR	VP_GLOBAL_CLI_JS_SCRIPTS_DIR	Vite+ only, mise compatibility

Other env variables, like VITE_PACK_ should be treated as Vite itself's internal env vars, should not be changed.

Opening Questions / Trade-off

We either mark these changes as a breaking change like #1166 or still read the old names for compatibility. The former is simple but maybe influence version handling, the latter may leave legacy code forever.

/cc @jong-kyung

[jong-kyung]

I agree with this direction. Since this is a cleanup of the remaining Vite+-specific environment variables that were not covered by the previous rename, I think we should rename them directly as a breaking change rather than introduce a gradual migration or backward compatibility for the old names.

@fengmk2 @wan9chi WDYT?

[wan9chi]

+1. I'll leave this to @fengmk2 to decide whether and how to do this.

[liangmiQwQ]

Okay! (I personally also support to mark it as a breaking change)