Add Symbol Font Google Material Symbols

[SJuliez]

This adds a font with a ton of icons, google's Material Symbols together with its license (Apache 2.0). These icons seem useful e.g. for marking hexes or other uses. Because of the way thy are centered, they are less useful for inlining with other text. Also adds a method in FontHandler to get that symbol font without having to remember its name.

[SJuliez]

@HammerGS You alright with this? It has a different license, Apache 2.0 (not OpenFont). Still seems ok to me.

[rjhancock]

Must provide appropriate credit but otherwise the licensing does not prevent its inclusion. The Apache License is actually more permissible than the OpenFont license in regards to fonts it seems.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 5 lines in your changes are missing coverage. Please review.

Project coverage is 29.11%. Comparing base (0742934) to head (132122f).
Report is 93 commits behind head on master.

❗ Current head 132122f differs from pull request most recent head 6c47614. Consider uploading reports for the commit 6c47614 to get more accurate results

Files	Patch %	Lines
.../src/megamek/client/ui/swing/util/FontHandler.java	0.00%	5 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5319      +/-   ##
============================================
+ Coverage     29.09%   29.11%   +0.02%     
- Complexity    13459    13473      +14     
============================================
  Files          2390     2389       -1     
  Lines        260774   260686      -88     
  Branches      46766    46747      -19     
============================================
+ Hits          75868    75900      +32     
+ Misses       181232   181121     -111     
+ Partials       3674     3665       -9     

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