为 extraRollupPlugins 增加灵活配置

[big-camel]

https://github.com/umijs/father/pull/279

https://github.com/umijs/father/issues/210

支持指定位置

before 在指定插件前插入

after 在指定插件后插入

replace 替换指定插件

import vue from 'rollup-plugin-vue'
import url from 'rollup-plugin-url';

export default {
    //在babel插件前插入 vue 插件
    extraRollupPlugins: [{ before: "babel", plugins: [vue()] }]
}

[codecov[bot]]

Codecov Report

Merging #338 (41ca81b) into master (48e823d) will decrease coverage by 0.44%. The diff coverage is 55.55%.

@@            Coverage Diff             @@
##           master     #338      +/-   ##
==========================================
- Coverage   73.57%   73.12%   -0.45%     
==========================================
  Files          16       16              
  Lines         473      480       +7     
  Branches      171      175       +4     
==========================================
+ Hits          348      351       +3     
- Misses        124      128       +4     
  Partials        1        1              

Impacted Files	Coverage Δ
packages/father-build/src/getRollupConfig.ts	93.68% <55.55%> (-4.05%)	:arrow_down:

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[tinymins]

功能不错，我需要在 babel 前面插入 eslint 插件也需要这个能力。建议把代码风格格式化下，然后完善测试用例，不然感觉会被一直挂起在这里。