Remove sharp (image manipulator) for now as not using it

Also it'll be in a plugin soon anyways so extra weight atm.

package.json

@@ -94,7 +94,6 @@
     "remark-html": "^5.0.1",
     "remark-parse": "^2.2.0",
     "sanitize-html": "^1.13.0",
-    "sharp": "^0.16.2",
     "slash": "^1.0.0",
     "static-site-generator-webpack-plugin": "^3.1.0",
     "style-loader": "^0.13.0",

yarn.lock

@@ -2039,7 +2039,7 @@ color@^0.10.1:
     color-convert "^0.5.3"
     color-string "^0.3.0"
 
-color@^0.11.0, color@^0.11.3:
+color@^0.11.0:
   version "0.11.3"
   resolved "https://registry.yarnpkg.com/color/-/color-0.11.3.tgz#4bad1d0d52499dd00dbd6f0868442467e49394e6"
   dependencies:
@@ -5105,7 +5105,7 @@ [email protected]:
   version "0.0.5"
   resolved "https://registry.yarnpkg.com/mute-stream/-/mute-stream-0.0.5.tgz#8fbfabb0a98a253d3184331f9e8deb7372fac6c0"
 
-nan@^2.3.0, nan@^2.4.0:
+nan@^2.3.0:
   version "2.4.0"
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.4.0.tgz#fb3c59d45fe4effe215f0b890f8adf6eb32d2232"
 
@@ -6758,7 +6758,7 @@ request-promise@^2.0.0:
     lodash "^4.5.0"
     request "^2.34"
 
-request@^2.34, request@^2.55.0, request@^2.58.0, request@^2.67.0, request@^2.74.0, request@^2.75.0, request@2.x:
+request@^2.34, request@^2.55.0, request@^2.58.0, request@^2.67.0, request@^2.74.0, [email protected]:
   version "2.75.0"
   resolved "https://registry.yarnpkg.com/request/-/request-2.75.0.tgz#d2b8268a286da13eaa5d01adf5d18cc90f657d93"
   dependencies:
@@ -6941,7 +6941,7 @@ semver@^4.3.3:
   version "4.3.6"
   resolved "https://registry.yarnpkg.com/semver/-/semver-4.3.6.tgz#300bc6e0e86374f7ba61068b5b1ecd57fc6532da"
 
-semver@^5.0.1, semver@^5.0.3, semver@^5.1.0, semver@^5.3.0, semver@~5.3.0, "semver@2 || 3 || 4 || 5":
+semver@^5.0.1, semver@^5.0.3, semver@^5.1.0, semver@~5.3.0, "semver@2 || 3 || 4 || 5":
   version "5.3.0"
   resolved "https://registry.yarnpkg.com/semver/-/semver-5.3.0.tgz#9b2ce5d3de02d17c6012ad326aa6b4d0cf54f94f"
 
@@ -7010,17 +7010,6 @@ [email protected]:
   version "2.2.6"
   resolved "https://registry.yarnpkg.com/sha.js/-/sha.js-2.2.6.tgz#17ddeddc5f722fb66501658895461977867315ba"
 
-sharp@^0.16.2:
-  version "0.16.2"
-  resolved "https://registry.yarnpkg.com/sharp/-/sharp-0.16.2.tgz#99381fb9dfbeaa89aa6d13ac77c5756b1e56e9e1"
-  dependencies:
-    bluebird "^3.4.6"
-    color "^0.11.3"
-    nan "^2.4.0"
-    request "^2.75.0"
-    semver "^5.3.0"
-    tar "^2.2.1"
-
 shebang-regex@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/shebang-regex/-/shebang-regex-1.0.0.tgz#da42f49740c0b42db2ca9728571cb190c98efea3"
@@ -7447,7 +7436,7 @@ tar-stream@^1.1.2:
     readable-stream "^2.0.0"
     xtend "^4.0.0"
 
-tar@^2.2.1, tar@~2.2.0, tar@~2.2.1:
+tar@~2.2.0, tar@~2.2.1:
   version "2.2.1"
   resolved "https://registry.yarnpkg.com/tar/-/tar-2.2.1.tgz#8e4d2a256c0e2185c6b18ad694aec968b83cb1d1"
   dependencies: