fix(git)!: use internal proxy for all git operations (#39426)

Introduces gitproxy module which spawns a small forward proxy as scanner
for git calls
Replaces hostmatcher with matchlist which supports port rules
Deprecates ALLOWED_DOMAINS/BLOCKED_DOMAINS and ALLOW_LOCALNETWORKS
settings in migration in favor of full names we have in security
configs.
Removes `external` preset in favor of lax/strict modes, strict mode
requiring explicit ports if they aren't standard http/s ones.

Breaking changes:
- `external` preset no longer works as deny rule. To enforce that, use
`strict` mode and allow ranges to connect to
- Wildcards are no longer accepted in IP addresses
- `*` is no longer allowed as entry in lists
- domain rules now use curl like syntax `*.example.com` matching
subdomains but not `example.com`, `example.com` matching itself and all
subdomains. `example.*` is not a valid rule
- In the default `lax` mode, `[security] ALLOWED_HOST_LIST` no longer
restricts public hosts, set `EGRESS_MODE = strict` to keep an exclusive
list. A startup warning flags this
- Invalid list entries are logged at startup, invalid
`BLOCKED_HOST_LIST`/`BLOCKED_DOMAINS` entries stop it

Docs: https://gitea.com/gitea/docs/pulls/557
Signed-off-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: bircni <bircni@icloud.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

options/locale/locale_en-US.json

@@ -1102,7 +1102,7 @@
   "repo.migrate.github_token_desc": "You can put one or more tokens here, separated by commas, to make migrating faster by circumventing the GitHub API rate limit. WARNING: Abusing this feature may violate the service provider's policy and may lead to getting your account(s) blocked.",
   "repo.migrate.clone_local_path": "or a local server path",
   "repo.migrate.permission_denied": "You are not allowed to import local repositories.",
-  "repo.migrate.permission_denied_blocked": "You cannot import from disallowed hosts. Please ask the admin to check ALLOWED_DOMAINS/ALLOW_LOCALNETWORKS/BLOCKED_DOMAINS settings.",
+  "repo.migrate.permission_denied_blocked": "You cannot import from disallowed hosts. Please ask the admin to check the ALLOWED_HOST_LIST/BLOCKED_HOST_LIST settings in the [migrations] section.",
   "repo.migrate.invalid_local_path": "The local path is invalid. It doesn't exist or is not a directory.",
   "repo.migrate.invalid_lfs_endpoint": "The LFS endpoint is not valid.",
   "repo.migrate.failed": "Migration failed: %v",