Add missing license headers

[romtsn]

#skip-changelog

📜 Description

Add missing license headers, or change them to adhere to the correct structure

💡 Motivation and Context

Closes #2619

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	389.49 ms	485.18 ms	95.69 ms
Size	1.72 MiB	2.29 MiB	576.50 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
c7e2fbc	377.85 ms	426.35 ms	48.50 ms
c7e2fbc	398.35 ms	468.52 ms	70.17 ms
0bf143e	368.35 ms	437.47 ms	69.12 ms
7ca9895	364.31 ms	460.46 ms	96.15 ms
c7e2fbc	393.98 ms	478.24 ms	84.27 ms
99a51e2	405.11 ms	479.65 ms	74.54 ms
4bf95dd	345.96 ms	414.24 ms	68.28 ms
c7e2fbc	372.00 ms	461.71 ms	89.71 ms

App size

Revision	Plain	With Sentry	Diff
c7e2fbc	1.72 MiB	2.29 MiB	576.40 KiB
c7e2fbc	1.72 MiB	2.29 MiB	576.40 KiB
0bf143e	1.72 MiB	2.29 MiB	576.50 KiB
7ca9895	1.72 MiB	2.29 MiB	576.51 KiB
c7e2fbc	1.72 MiB	2.29 MiB	576.40 KiB
99a51e2	1.72 MiB	2.29 MiB	576.34 KiB
4bf95dd	1.72 MiB	2.29 MiB	576.40 KiB
c7e2fbc	1.72 MiB	2.29 MiB	576.40 KiB

Previous results on branch: rz/chore/add-license-headers

Startup times

Revision	Plain	With Sentry	Diff
7cceaa2	414.71 ms	493.61 ms	78.90 ms

App size

Revision	Plain	With Sentry	Diff
7cceaa2	1.72 MiB	2.29 MiB	576.50 KiB

[Marcono1234]

It seems this is wrong; ISO8601UtilsTest.java was retroactively added to Gson by google/gson#1638 and is not based on jackson-databind's ISO8601UtilsTest.java.

(Please correct me if I am wrong though)