feat: update all dependencies and modernize the source base

[azlekov]

This is first of many PRs which I want to introduce in order to get this SDK up to date.

First step in my master plan is update all dependencies, Gradle version and used plugins. Also this PR will cover updating to Java 8 and taking advantage of all sweet features of it. I prefer to make a small incremental steps so the PRs to be easy to review.

Code optimisation which have been done:

• Replace all anonymous classes with lambdas where possible.
• Make all fields final where possible
• Internal classes as static where possible
• Replace test assertions with context ones
• Use diamond <> where possible
• Use method references where possible
• Imports re-arrange

NOTE: No business logic was changed so far

Updating of the Firebase Messaging should address https://github.com/parse-community/Parse-SDK-Android/issues/1071#issuecomment-840608858 as there introduce some breaking changes and when using the Parse FCM there are signature issues with latest version of FCM

[azlekov]

Hello @Jawnnypoo @mtrezza I finally dared to submit my first PR here. Not sure if you are the right persons to ping, but I saw you're more likely active here. Don't be afraid of the huge changes, most of them are just replacing callbacks with lambdas and just syntax sugaring around Java 8.

I will be very happy if you have time to check this PR.

[rogerhu]

Thanks for the work!

[Jawnnypoo]

@L3K0V Looks like there is a compilation issue:

Parse-SDK-Android/parse/src/main/java/com/parse/ParseCommandCache.java:110: error: variable context might not have been initialized

[azlekov]

@Jawnnypoo any ideas what can cause this? On this line there's nothing interesting....

[Jawnnypoo]

Hmm yeah I am not really sure. Maybe you can remove this check.

[azlekov]

Fun fact is that locally I'm able to run the same Gradle script as the GitHub CI and it's working.

[codecov[bot]]

Codecov Report

:exclamation: No coverage uploaded for pull request base (master@0362b10). Click here to learn what that means. The diff coverage is 63.03%.

@@            Coverage Diff            @@
##             master    #1095   +/-   ##
=========================================
  Coverage          ?   65.06%           
  Complexity        ?     2208           
=========================================
  Files             ?      122           
  Lines             ?     9463           
  Branches          ?     1317           
=========================================
  Hits              ?     6157           
  Misses            ?     2799           
  Partials          ?      507           

Impacted Files	Coverage Δ
.../src/main/java/com/parse/CacheQueryController.java	6.81% <0.00%> (ø)
...c/main/java/com/parse/KnownParseObjectDecoder.java	50.00% <ø> (ø)
...arse/src/main/java/com/parse/LocationNotifier.java	0.00% <0.00%> (ø)
parse/src/main/java/com/parse/LockSet.java	0.00% <0.00%> (ø)
...rc/main/java/com/parse/OfflineQueryController.java	100.00% <ø> (ø)
parse/src/main/java/com/parse/ParseACL.java	89.15% <ø> (ø)
.../main/java/com/parse/ParseAnalyticsController.java	100.00% <ø> (ø)
...e/src/main/java/com/parse/ParseAnonymousUtils.java	57.14% <ø> (ø)
...rse/src/main/java/com/parse/ParseCommandCache.java	2.22% <0.00%> (ø)
...java/com/parse/ParseCountingByteArrayHttpBody.java	82.35% <ø> (ø)
... and 64 more

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