Migrate to gitea

Usage:

With key over ssh
```
./migrate.sh \
    --admin gitea_user \
    --url http://gitea.example.com \
    --token TOKEN_VALUE \
    --pushurl ssh://git@gitea.example.com:3022 \
    "ARG 1" ... "ARG N"
```
With password over http
```
./migrate.sh \
    --admin gitea_user \
    --url http://gitea.example.com \
    --token TOKEN_VALUE \
    --password PASSWORD_VALUE \
    "ARG 1" ... "ARG N"
```
ARG format: ``"/path/to/repo:ORG_NAME:REPO_NAME"``

examples:
```
    # only path to repo - owner will be $GITEA_ADMIN_USERNAME
    # name will be result of $(basename "/path/to/repo" ".git")
    /path/to/repo

    # org only
    /path/to/repo:ORG_NAME

    # org and name 
    /path/to/repo:ORG_NAME:REPO_NAME

    # name only - owner will be $GITEA_ADMIN_USERNAME
    /path/to/repo::REPO_NAME
```
configuration can be done with file ``./init.sh``
```
GITEA_ADMIN_USERNAME="$USER"
GITEA_SERVER_PUSH_URL="ssh://git@gitea.example.com:3022"
GITEA_ADMIN_TOKEN="TOKEN_VALUE"
GITEA_SERVER_URL="http://gitea.example.com"
```

Required commands:
```
git
curl
```