Reworked synchashes so that it expects commits to be inserted as an input parameter

[renatav]

• A json containing all commits which are to be inserted into the database is expected to be passed into synchashes. This json can contain commits belonging to different repositories. An example of this file:

  {
  "cityofsanmateo/law-html": {
      "publication/2020-04-03-01": [
          {
              "commit": "36a3b106bc1c1d089511d4826bfb3bc38f95e73b",
              "additional-info": {
                  "build-date": "2020-04-03",
                  "codified-date": "2019-02-04"
              }
          },
          {
              "commit": "a9b78f8fb8879026a6cc920a3388553c05bb04dc",
              "additional-info": {
                  "build-date": "2020-04-03",
                  "codified-date": "2019-04-01"
              }
          },
          {
              "commit": "a16117875399618916f05d6d0023e4aa35af3b44",
              "additional-info": {
                  "build-date": "2020-04-03",
                  "codified-date": "2019-05-01"
              }
          },
          {
              "commit": "2ea9ef6ca0b1b33909e866f4fc1e65fe5747a644",
              "additional-info": {
                  "build-date": "2020-04-03",
                  "codified-date": "2019-05-06"
              }
          }
      ]
  },
  "cityofsanmateo/law-docs": {
      "master": [
          {
              "commit": "9bbea7b975593e6993c48dc24dcba5e6199c8369",
              "additional-info": {
                  "build-date": "2020-04-03"
              }
          }
      ]
  }
  }

• synchashes also expects path to the library root and expects library structure which is the same as the one that taf expects.

• Updated tests in accordance with the rework

• Removed git hooks

Close #2 Depends on https://github.com/openlawlibrary/taf/pull/133.